IRLF 


ORGANIC  CHEMISTRY 

-FOR  THE- 

LABORATORY. 


— BY— 

w.  A.  NOYBS,  F»H.E>., 

• 

PROFESSOR  OF  CHEMISTRY  IN  ROSE  POLYTECHNIC  INSTITUTE, 
TERRE  HAUTE,  IND. 


E ASTON,  PA.: 

CHEMICAL  PUBLISHING  CO. 

1897. 


COPYRIGHT,  1897,  BY  EDWARD  HART. 


PREFACE. 


The  science  of  organic  chemistry  rests,  for  its  experi- 
mental foundation,  on  the  preparation,  usually  by  syn- 
thetical means,  of  pure  compounds.  Without  a  knowl- 
edge, based  on  personal  experience  in  the  laboratory,  of 
the  relations  involved  and  the  methods  which  may  be 
used  in  such  preparations,  no  satisfactory  knowledge  of 
the  science  can  be  acquired.  It  has  been  the  purpose  of 
the  author  in  writing  this  book  to  classify  the  most  im- 
portant of  the  laboratory  processes  which  have  been  used 
in  the  development  of  the  science  and  to  illustrate  them 
by  concrete  examples. 

Two  distinct  purposes  have  been  kept  in  view.  The 
first  has  been  to  furnish  the  beginner  with  sufficiently 
full  and  accurate  directions,  and  clear,  concise,  theo- 
retical explanations  of  processes  which  have  been  found 
successful  in  practical  laboratory  experience.  The 
second  object  has  been  to  furnish  the  more  advanced 
student  and  practical  worker  with  a  guide  which  will 
aid  him  in  the  selection  of  processes  which  are  likely  to 
be  successful  for  the  preparation  of  compounds  which  he 
may  desire  to  use. 

It  is  for  this  second  reason,  partly,  that  the  number 
of  preparations  given  is  considerably  greater  than  it 


IV  PREFACE. 

would  be  profitable  for  the  average  student  to  prepare, 
and  that  the  references  to  the  literature  have  been  made 
quite  full. 

The  student  who  uses  the  book  is  very  earnestly  ad- 
vised to  begin  each  preparation  with  a  careful  study  of 
the  directions  given,  and  also  of  the  literature  of  the 
subject.  For  the  time  being,  he  should  make  himself 
thoroughly  familiar  with  all  of  the  important  relations 
of  the  substance  with  which  he  is  working,  and  with 
other  methods  of  preparation  which  might  be  used.  A 
comparatively  few  preparations  carefully  studied  in  this 
way  will  be  of  greater  value  than  a  much  larger  number 
mechanically  executed  by  simply  following  the  directions 
of  the  book.  The  successful  student  must  be  able  to 
use  intelligently  the  larger  handbooks,  especially  that 
of  Beilstein,  and  the  original  sources  in  chemical  jour- 
nals. It  need  scarcely  be  remarked  that  a  satisfactory 
working  knowledge  of  organic  chemistry  cannot  be  ac- 
quired without  the  ability  to  use  German  books. 

In  some  cases  it  may  be  well  to  undertake  the  prepa- 
ration of  analogous  substances  in  place  of  the  ones 
which  are  given.  The  majority  of  the  processes  de- 
scribed should  be  viewed  from  the  standpoint  that  they 
are  applicable  to  many  other  similar  cases,  though 
slight  modifications  are  often  necessary,  and  as  to  that 
the  student  should  satisfy  himself  by  examination  of 
the  literature  before  he  goes  on  with  his  work.  In  re- 
search work  chemists  very  often  help  themselves  by  a 
careful  study  of  the  properties  of  bodies  related,  or  anal- 
ogous to  those  which  they  wish  to  prepare,  and  the 


PREFACE.  V 

habit  of  making  comparisons  of  this  kind  is  very  valua- 
ble. 

It  is  not  the  intention  of  the  author  that  the  order  of 
the  book  should  be  necessarily,  or,  indeed,  usually  fol- 
lowed by  the  student.  He  has  a  very  firm  conviction 
that  laboratory  work  of  the  sort  provided  for  in  this  book 
should  always  accompany  the  lecture-room  or  text-book 
work  in  organic  chemistry,  and  that  the  frequent  lack  of 
interest  in  the  subject  is  often  due  to  the  fact  that  the 
laboratory  work  is  given  a  year  or  two  after  the  lectures, 
or  that  it  is  omitted  altogether.  If  the  book  is  used  in 
conjunction  with  the  usual  course  of  lectures  to  begin- 
ners, as  it  is  hoped  that  it  may  be,  topics  will  naturally 
be  selected  in  the  same  general  order  as  that  followed  in 
the  lectures  or  text-book. 

The  discussion  of  special  topics,  such  as  crystalliza- 
tion, filtration,  distillation,  distillation  under  diminished 
pressure,  extraction,  etc.,  has  been  given  in  connection 
with  preparations  when  their  use  is  required.  Frequent 
references  to  these  discussions  are  given  elsewhere,  and 
they  may  also  be  readily  found  by  means  of  the  index. 

The  author  wishes  to  acknowledge  his  indebtedness 
to  the  somewhat  similar  works  of  L,evy,  Gettermann, 
Krdmann,  and  H.  Fischer  for  many  suggestions  ;  also  to 
a  little  book  by  Drs.  A.  A.  Noyes  and  S.  P.  Mulliken 
on  the  "Class  Reactions  of  Organic  Substances",  for 
some  suggestions  in  writing  the  chapter  on  the  qualita. 
tive  examination  of  organic  substances.  He  also  de- 
sires to  express  his  thanks  to  Mr.  W.  K.  Burk,  who  pre- 
pared the  drawings  for  the  book,  and  to  Mr.  J.  J.  Kess- 


VI  PREFACE. 

ler,  Jr.,  who  has  tested  many  of  the  directions  for  prep- 
arations in  the  laboratory.  I  wish  also  to  express  my 
sincere  thanks  to  Dr.  J.  Bishop  Tingle,  who  has  read 
carefully  all  of  the  proofs,  and  has  made  many  valuable 
suggestions. 


OF  CONTENTS. 


CHAPTER  L 

ACIDS i 

1.  Isovaleric  acid  from  amyl  alcohol 12 

2.  Propionic  and  butyric  acids  from  dipropylketone 18 

3.  Camphoric  acid  from  camphor 20 

4.  Benzoic  acid  from  benzyl  chloride 23 

5.  Nitrobenzoic  acids  from  toluene  by  nitration  and  oxida- 

tion   24 

6.  Succinic  acid  from  ethylene  bromide  through  the  cy- 

anide    32 

7 .  Malonic  ester  from  chloracetic  acid 34 

8.  Mandelic  acid  from  benzaldehyde  through  the  cyanhy- 

drin  37 

9.  Paratoluic  acid  from  paratoluidine  through  tolunitrile-  42 

10.  Acetacetic  ester  by  condensation 44 

n.  Diacetylsuccinic  ester  from  acetacetic  ester 51 

12.  Succinylo-succinic   ester 53 

13.  Hydrocinnamic   acid   from   acetacetic  ester  and   benzyl 

chloride ;   benzyl  acetone 55 

14.  Cinnamic  acid ;  Perkin's  synthesis 58 

15.  Cinnamic  acid  from  benzaldehyde  through  benzylidene 

acetone 59 

16.  Formic  acid  from  oxalic  acid 61 

17.  Stearic  acid  from  tallow 63 

18.  Uric  acid  from  urine 65 

19.  Levulinic  acid  from  a  hexose 67 

CHAPTER  IL 

DERIVATIVES  OF  ACIDS 70 

20.  Acetyl  chloride  from  acetic   acid   and   phosphorus   tri- 

chloride    76 


Vlll  CONTENTS. 

21.  Acetic  anhydride 78 

22.  Succinic  anhydride  from  succinic  acid  with  phosphorus 

oxychloride 79 

23.  Acetamide  by  heating  ammonium  acetate 80 

24.  Carbamide  from  phosgene  and  ammonia  (Urea) 82 

25.  Phenyl  sulphonamide  from  benzene 83 

26.  Phenyl  benzoate,  Schotten-Baumann's  reaction 85 

27.  Acetanilide  from  aniline  and  acetic  acid 86 

28.  Ethyl  acetic  ester  from   alcohol    and    acetic   and   sul- 

phuric acids  ^ 87 

29.  Ethyl  succinic  ester  from  alcohol  and  succinic  and  sul- 

phuric acids 89 

30.  Diacetyl  tartaric  ethyl  .ester,  esterification  with  hydro- 

chloric acid  and  by  the  Schotten-Baumann  reaction . .     89 

31.  Benzoic  ethyl  ester  through  benzoyl  chlorid,e 92 

32.  ^-Brombutyric  acid  by  bromination   with  bromine  and 

phosphorus 93 

33.  Metanitrobenzoic  acid  by  nitration  of  benzoic  acid 95 

34-  Glycocoll  from  chloracetic  acid 97 

35.  Anthranilic    acid    from    phthalic     anhydride   through 

phthalamidic  acid 99 

36.  Salicylic  acid ;    Kolbe's  synthesis 101 

37.  Hydrocinnamic  acid  by  reduction  of  cinnamic  acid 103 

CHAPTER  III. 

HALOGEN  COMPOUNDS 105 

38.  Methyl   iodide   from   methyl  alcohol,  phosphorus   and 

iodine 108 

39.  Ethyl  bromide  from  alcohol,  sulphuric  acid  and  potas- 

sium bromide 109 

40.  Paradibrombenzene  by  direct  bromiuation in 

41.  Benzyl  chloride  from  toluene 112 

42.  Parabromtoluene  from   paratoluidine,  Sandmeyer's  re- 

action      114 

43.  Ethylene  bromide  from  ethylene  and  bromine  •< 117 

44.  Chloroform  from  acetone  and  calcium  hypochlorite 119 


CONTENTS.  IX 

CHAPTER  IV. 

NITRO  COMPOUNDS 121 

45.  Metadinitrobenzene  by  direct  nitration 123 

46.  Metanitrotoluene  from  paratoluidine 124 

47-  #-Nitronaphtylamine 127 

48.  Orthonitroparatoluidine  by  direct  nitration  of  toluidine  128 

CHAPTER  V. 

AMINES * 130 

49.  Aniline  by  reduction  of  nitrobenzene 133 

50.  Orthonitroparatoluidine  from  toluene  through  the  dini- 

tro  compound  by  reduction  with  ammonium  sulphide  135 

51.  Paradiaminobenzene  from  acetanilide 136 

52.  Diethylamine  from  aniline  and  ethyl  bromide  through 

paranitrosodiethy  1  amine • 138 

53.  Isopropyl  aniiue  by  reduction  of  acetoxime 140 

54-  Gtf-Phenylethylamine   from  benzoyl    chloride    through 

benzyl  cyanide 142 

55.  Benzyl  amine 144 

CHAPTER  VI. 

HYDRAZO,  Azo,  DIAZO  COMPOUNDS,  ETC 148 

56.  Hydrazobenzene 153 

57 .  Azobenzene 154 

58.  Aminoazobenzene 1 55 

59.  Sulphobenzene-azo-fi-naphtylamine 157 

60.  Diazobenzene  chloride 159 

61.  Phenyl  hydrazine   by  reduction   of  diazobenzene   with 

stannous  chloride 160 

62.  Glucosazone 162 

CHAPTER  VII. 

ALCOHOLS  AND  PHENOLS 164 

63.  Ethylene  glycol 166 

64.  Methylphenylcarbinol  by  reduction  of  acetophenone.  ••  167 

65.  Paracresol  from  paratoluidine,  Griess'  reaction 168 

66.  Hydroquinone  from  aniline 170 


X  CONTENTS. 

67.  Alizarin  from  anthraquinone 172 

68.  Allyl  alcohol  from  glycerol 175 

69.  Benzyl  alcohol  from  benzaldehyde 176 

CHAPTER  VIIL 

ALDEHYDES,  KETONES,  AND  THEIR  DERIVATIVES 178 

70.  Acetaldehyde 181 

71.  Benzophenone     from   benzoyl  chloride,    benzene,     and 

aluminium  chloride 184 

72.  Benzaldehyde  from  benzyl  chloride 187 

73-  Benzoin  ;  condensation  by  potassium  cyanide 188 

74.  Anthraquinone  by  oxidation  of  anthracene 190 

75-  Phenyl  hydrazone  of  acetophenone 191 

76.  Acetoxime 192 

77-  Semicarbazone  of  acetone  • 193 

78.  Furfural  from  a  pentosan 196 

CHAPTER  IX. 

SULPHONIC  ACIDS  AND  SULPHINE  COMPOUNDS 198 

79-  Sulphanilic  acid 200 

80.  Ortho-  and  paratoluene  sulphonamides  from  toluene- ..  201 

81.  Trimethyl  sulphine  iodide 203 

CHAPTER  X. 
HYDROCARBONS 205 

82.  Benzene  from  benzoic  acid 209 

83.  Paraxylene   from  parabromtoluene,  methyl   iodide  and 

sodium 209 

84.  Triphenylmethane — Friedel  and  Craft's  synthesis 210 

85.  Cymene  from  camphor 212 

86.  Diphenyl  from  benzene  by  heat 213 

87.  Diphenylmethane  from  benzophenone 214 

88.  Anthracene  from  alizarin 215 

CHAPTER  XL 
MISCELLANEOUS  COMPOUNDS 217 

89.  Quinoline — Skraup's  synthesis 217 


CONTENTS.  XI 

go.  Phenol  phthalein 2l8 

91.  Collidindicarboxyllic  ethyl  ester   220 

92.  Antipyrine 222 

93.  Thiophen 224 

94.  Orthobenzoylbenzoic  acid 225 

95.  Phenyl  cyanide 227 

96.  Zinc  ethyl 228 

CHAPTER  XIL 

Qualitative  examination  of  organic  compounds 231 

Reagents 24° 


Acids* 

I.  Oxidation  of  Alcohols,  Aldehydes,  Ketones,  and 
Hydrocarbons. — The  oxidation  is  usually  effected  by  a 
mixture  of  potassium  pyrochromate,  sulphuric  acid,  and 
water,  by  dilute  nitric  acid,  or  by  potassium  permanga- 
nate in  alkaline  solution. 

With  the  chromic  acid  mixture  the  first  product  of  the 
oxidation  of  an  alcohol  is  probably  an  aldehyde  or 
ketone.  In  the  case  of  ethyl  alcohol  the  aldehyde  is  so 
volatile  as  to  escape  rapidly  as  soon  as  formed  and  the 
method  cannot  be  practically  used  for  the  preparation  of 
acetic  acid. 

With  some  of  the  higher  alcohols  of  the  same  series 
the  acid  which  is  formed  by  the  oxidation  of  a  part  of 
the  alcohol  combines  with  another  portion  of  the  alcohol 
to  form  an  ester.  The  continued  action  of  the  oxidizing 
mixture  may  saponify  the  ester  and  complete  the  oxida- 
tion of  the  alcohol,  but  it  is  sometimes  better  to  moder- 
ate its  action  so  that  the  ester  is  the  chief  product  of  the 
oxidation  and  to  secure  the  acid  by  the  saponification  of 
the  latter  (isovaleric  acid). 

The  oxidation  of  open  chain  ketones  and  of  secondary 
alcohols  can  give  rise  to  the  formation  of  acids  only  by 
separating  the  molecule  into  two  parts.  The  carbonyl 
of  the  ketone  usually,  but  not  always,  goes  with  the 


2  ORGANIC   CHEMISTRY. 

smaller  part.  There  may  result  a  single  acid,  as  in  the  case 
of  methyl  ethyl  ketone  (2-butanone) ,  or  two  acids,  as  with 
dipropyl  ketone  (^-heptanone)  or  propyl  methyl  ketone 
(2-pentanone) .  In  the  latter  case,  for  purposes  of  inves- 
tigation, the  separation  of  homologous  fatty  acids  becomes 
important.  This  can  be  effected  by  distilling  an  aqueous 
solution  of  the  acids.  The  acid  of  higher  molecular  weight 
passes  over  first  with  the  water  vapor,  apparently  because 
it  is  less  soluble  in  water.  By  preparing  silver  salts  of 
the  acids  in  the  first  and  last  portions  of  the  distillate 
the  composition  of  the  acids  formed  can  be  established. 
(See  2,  p.  18,  separation  of  propionic  and  butyric  acids) . 

The  oxidation  of  cyclic  ketones,  and  in  some  cases  of 
other  cyclic  compounds,  gives  rise  to  the  formation  of 
bi-basic  acids  (camphoric  acid). 

In  the  benzene  series,  side  chains  consisting  of  alkyl 
(CH3,  C2H6,  etc.)  or  other  groups  in  which  a  carbon 
atom  is  combined  directly  with  the  benzene  nucleus, 
can  be  oxidized  to  carboxyl.  In  the  case  of  hydrocar- 
bons, the  oxidation  is  usually  effected  with  difficulty, 
partly  owing  to  their  insolubility  in  the  oxidizing  agents 
employed.  On  this  account  it  is  sometimes  advisable  to 
prepare,  at  first,  a  halogen  derivative  having  the  hal- 
ogen in  the  side  chain  (Baeyer :  Oxidation  of  paraxylene, 
Ann.  Chem.  (L,iebig) ,  245, 138 ;  benzoicacid,  4»  p.  23.) 

II.  Saponification  of  Cyanides. — The  cyanides  of  or- 
ganic radicals,  or  "nitriles"  of  acids,  may  be  obtained 
from  halogen  derivatives  of  hydrocarbons,  salts  of  acid 
sulphuric  esters  of  alcohols,  or  salts  of  sulphonic  acids 
by  treating  with  potassium  cyanide.  The  last  two 


ACIDS.  3 

cases  are  applicable  only  when  the  cyanide  formed  can 
be  distilled  from  the  dry  mixture  without  decomposi- 
tion. 

Nef  has  shown  that  potassium  cyanide  has  the  struc- 
ture K — N=C,  and  the  reaction  probably  takes  place 
in  two  stages  : 

K— N=C  +  RC1    =     K— N=C<^! 

=NEEEC— R+KC1. 

A  small  amount  of  an  isocyanide  is  formed  at  the 
same  time,  the  group  — N  =  C  taking  the  place  of  the 
halogen  or  acid  group  of  the  organic  compound. 

Cyanhydrines,    which  by  saponification    give   tf-hy- 
droxy  acids,  can  be  prepared  by  treating  aldehydes  or 
ketoues  with  hydrocyanic  acid,  best  in  the  nascent  state: 
R  R  OH 

V=0+HCN   =       V/        . 
R'  R'     XCN 

From  aromatic  amines  cyanides  can  be  obtained  by 
treating  the  diazo  compound  with  cuprous  cyanide. 
(Sandmeyer.) 

R— NHaHCl  +  HNOa  =  R— N=N+2H2O, 

I 
Cl 

2R— N=N+CuCaNa  =  2R— CN+CU.C1,. 

Cl 

The  cuprous  cyanide  for  the  reaction  is  prepared  from 
copper  sulphate. 

CuSO4  +  2KCN  =  Cu(CN)a  +  KaSO4, 
2Cu(CN)a  =  Cua(CN)a  +  (CN  ).. 


4  ORGANIC   CHEMISTRY. 

The  saponification  of  cyanides  is  usually  effected 
either  by  the  action  of  an  aqueous  or  alcoholic  solution 
of  potassium,  sodium,  or  barium  hydroxide,  or  by  the 
action  of  hydrochloric  or  sulphuric  acid.  An  amide  of 
the  organic  acid  is  probably  always  an  intermediate 
product  of  the  saponification  and,  in  some  cases,  the 
conversion  of  the  cyanide  into  an  amide  and  the  conver- 
sion of  the  latter  into  the  acid  may,  with  advantage,  be 
carried  out  in  two  stages  and  by  means  of  different 
agents. 

O 

R— C  =  N  +  HaO  =  R  — C  — NH3, 

O  O 

/  S 

R  — C  — NHa  +  KOH  =   RC  —  OK  +  NH3,    or 

O  O 

/  / 

R  — C  —  NHa+HaO  +  HCl  =  RC  —  OH  +  NH4C1. 

III.  Condensation. — By  condensation,  in  general,  is 
meant  the  formation  of  a  compound  from  two  others 
with  the  elimination  of  water,  alcohol,  ammonia,  hydro- 
chloric acid,  or  two  halogen  atoms.1  Methods  of  conden- 
sation have  been  especially  useful  in  the  synthesis  of 
acetacetic  ester  and  its  derivatives,  cinnamic  acid,  and 
of  many  other  compounds  in  which  the  same  principles 
have  been  applied. 

1  Some  authors  use  the  term  condensation  exclusively  as  applied  to  reac- 
tions in  which  carbon  atoms  unite,  and  especially  with  the  elimination  of 
water  or  alcohol,  but  there  appears  to  be  no  logical  reason  for  such  a  restric- 
tion in  its  use. 


ACIDS.  5 

In  the  case  of  acetacetic  ester  the  condensation  ap- 
pears to  take  place  as  follows  : 

CH3COjOC2HB+  H;CH3C02C3H6  =  CH8COCH3CO3C3H6 
+  C2H6OH. 

The  researches  of  Claisen  indicate,  however,  that  the 
action  consists,  at  first,  in  the  addition  of  sodium  ethyl- 
ate,  formed  from  a  trace  of  alcohol  which  is  always  pres- 
ent in  acetic  ester,  to  the  ester,  thus  : 

^O  /ONa 

CH3Cf  +  NaOC2HB   =    CH3— C— OC2H6. 

XOC3H6  \OC2H5 

The  addition  product  then  condenses  with  a  second 
molecule  of  acetic  ester  thus  : 

/ONa 

CH8  —  C— !OC2H;      H3JCH.CO2C3H5  = 
\|OC2H6 

ONa 
/ 
CH8  —  C  =  CH.CO2C3H5  +  2C2H5OH. 

According  to  this  view,  on  the  addition  of  an  acid  a 

OH 

/ 
compound    of    the    formula  CH3—C=  CH  —  CO2C3H6 

would  be  liberated.  A  very  large  amount  of  work  has 
been  done  for  the  purpose  of  discovering  whether  acet- 
acetic ester  and  similar  bodies  have  the  "  enol"  (un- 
saturated  alcoholic)  or  ketone  structure.  In  spite  of 
this,  those  who  have  studied  the  subject  most  carefully 
have  not,  apparently,  come  to  any  general  agreement. 
It  would  seem  that  bodies  of  this  character  pass  very 


0  ORGANIC    CHEMISTRY. 

readily  from  one  form  into  the  other  and  that  while,  in 
some  cases,  the  bodies  in  question  may  consist  exclu- 
sively of  the  one  or  other  form,  in  others  they  are,  in  all 
probability,  mixtures  of  the  two  forms.  Therefore 
the  bodies  in  question  may  react  in  one  or  the  other 
form  or  in  both,  according  to  the  reagents  used,  one 
form  passing  over  into  the  other,  as  the  one  or  other 
form  disappears  in  the  progress  of  the  reaction. 

Very  closely  analogous  to  the  preparation  of  acet- 
acetic  acid  is  the  preparation  of  succinylosuccinic  ester 
by  the  condensation  of  succinic  ester. 

C02C,H6 
NaO  CO2C2Hfi  | 

\     i     or H          j  I  Na°        C 

Ci<or2H6    HJC  \^     \ 

|  i 5S5a i  |  C        CH2 

CH2  CH2  ~  || 

I  !        c  H'O1       '  CH'       C~ONa 

C!H2   p2SBrV>C— ONa  \     ^ 

|  !         S11*0;  C 

C02C2H5  | 

COQC2H5 

Succinic  ester  -f  Sodium  salt  of  succinyl- 

sodium  ethylate.  osuccinic  ester. 

By  the  action  of  sodium  ethylate  on  mixtures  of  esters 
or  of  esters  and  ketonesor  aldehydes,  many  similar  con- 
densations may  be  effected.  In  every  case  one  ester  group, 
after  adding  sodium  ethylate,  condenses  with  an  ethyl 
or  methylene  group  which  is  adjacent  to  the  carbonyl  of  a 
ketone  or  of  an  ester  group.  That  the  methin  group 
(CH)  is  not  susceptible  to  this  sort  of  condensation  is 


ACIDS.  7 

one  of  the  proofs  for  Claisen's  view,  referred  to  above 
(Ber.  d.  chem.  Ges.,  20,  651  ;  21,  1154). 

Acetacetic  ester  and  similar  compounds  which  con- 
tain a  methylene  or  methin  group  between  two  carbonyl 
or  ester  groups  give  sodium  salts  when  treated  with 
sodium  ethylate.  In  some  cases  cyanogen  or  other 
groups  may  have  the  same  effect  as  carbonyl.  Accord- 
ing to  the  views  of  some,  in  these  sodium  salts  the 
sodium  is  combined  with  oxygen  ("  enol"  form,  see 
above) ;  according  to  others  it  is  combined  with  carbon 
(ketone  form).  When  these  sodium',  silver,  or  copper 
salts  of  acetacetic  ester,  malonic  ester,  and  similar 
compounds  are  treated  with  alkyl  iodides,  acid  chlorides, 
or  other  halogen  derivatives,  compounds  are  formed  in 
which  the  alkyl  or  other  groups  are  sometimes  com- 
bined with  carbon  and  sometimes  with  oxygen. 

ONa 
/ 

CH3— C=CH— C02C,H5+CH3I  = 

ONa  CH3 
/        / 

CH3— CI—  CH— C02C2H6  = 

CH3 
/ 
CH3— CO— CH— CO2C2H6+NaI, 

Na 
/ 
or  CH3— COCH— CO2C2H6+CH3I  = 

CH3 
/ 
CH3— CO— CH— C01CiH.+NaI, 


ORGANIC  CHEMISTRY. 

Ocu 


CH3—  C=CH—  C02C2H5+CHSCOC1  = 

O—  COCHS 
X 

CH3—  C=CH—  CO.C.H.+CUC1.1 

(See  Nef  :  Ann.  Chem.  (Liebig),  266,   103,.  no,  and 
287,  270.) 

With  alkyl  iodides,  compounds  containing  the  alkyl 
combined  with  carbon  are  almost  exclusively  formed. 

This  method  has  been  of  very  great  value  in  obtain- 
ing derivatives  of  acetacetic  ester,  CH3COCHQCO2C2H6, 

OO  O  T-T 

malonic  ester,  CH2<Cp2p2TTB>  and  other  compounds. 


Acetacetic  acid  and  almost  all  other  /?-ketonic  acids  are 
extremely  unstable  in  the  free  state.  Hence,  if  the  esters 
of  these  acids  are  saponified,  decomposition  products  are 
usually  obtained,  instead  of  the  free  acid.  These  products 
vary  according  to  the  nature  of  the  ester  and  the  means 
used  for  its  saponification.  In  general,  saponification 
with  acids  causes  decomposition  with  loss  of  carbon  di- 
oxide and  formation  of  a  ketone  (ketonic  decomposi- 
tion) : 

CH3COCH2CO2C2H&  +  H2SO4  +  H2O  = 
Acetacetic  ester. 
CH3COCH8  +  C2H6OH  +  H2SO4  +  CO2. 

Acetone. 

(See  also  Baeyer  :  Ann.  Chem.    (Liebig),   278,    90,   for 
the  saponification  of  succinylosuccinic  ester.) 

i  In  this  case  "cu  "  is  used  to  represent  an  equivalent  instead  of  an  atom  of 
copper. 


ACIDS.  9 

Saponification  with  strong  bases,  on  the  other  hand, 
tends  to  favor  the  formation  of  acids  (acid  decomposi- 
tion). 

CH3COCHaC08CaH5+2KOH  = 

CH3COaK  +  CH3COaK  +  C2H6OH. 

Free  malonic  acid  and  its  derivatives,  that  is,  all 
compounds  having  two  carboxyls  combined  with  the 
same  carbon  atom,  although  stable  at  ordinary  tempera- 
tures, are  decomposed  when  heated  to  i5o°-2oo°,  and 
many  of  them,  also,  when  heated  with  moderately  strong, 
not  concentrated,  sulphuric  acid.  The  value  of  acet- 
acetic  ester  for  synthetic  purposes  is  lessened  because 
of  the  difficulty  of  securing  a  clean  "  acid  decomposi- 
tion" and,  since  the  same  product  may  usually  be  ob- 
tained by  the  use  of  malonic  ester,  the  latter  is  now 
more  frequently  used  in  syntheses. 

Another  method  of  condensation  used  for  the  prepara- 
tion of  acids,  known  as  Perkin's  synthesis  (Perkin  : 
Ann.  Chem.  (Liebig),  147,  230;  Ber.  d.  chem.  Ges.,  8, 
T599  I  JSD-  d.  Chem.,  ^£77,  789;  Tiemann,  Herzfeld  : 
Ber.  d.  chem.  Ges.,  10,  63),  consists  in  heating  a  mix- 
ture of  an  aldehyde,  a  sodium  salt,  and  acetic  anhy- 
dride. One  of  the  most  common  illustrations  is  the  syn- 
thesis of  cinnamic  acid,  which  appears  to  take  place  as 
follows  : 


C6H5CHjO  +  HajCHCOaNa  = 
Benzaldehyde. 

C6H6CH=CHCOaNa  +  H9O. 
Sodium  cinnatnate. 


10  ORGANIC  CHEMISTRY. 

The  reaction  has  been  shown  to  take  place  in  two 
stages  and  consists,  first,  in  an  addition  of  the  sodium 
salt  to  the  aldehyde  group  : 

.O  /OH 

C6H6C^     +  HCH2C02Na  =  C6H6C— CH2CO2Na. 
XH  \H 

This  addition  is  followed,  under  the  influence  of  the 
acetic  anhydride,  by  loss  of  water.  The  addition 
always  takes  place  with  the  methyl,  methylene  or  me- 
thin  group  adjacent  to  the  carboxyl.  Unlike  the  acet- 
acetic  ester  syntheses,  the  addition  may  take  place  with 
a  methin  group  as  well  as  with  methyl  and  methylene 
groups,  but  in  that  case  there  can  be  no  loss  of  water, 
and  a  hydroxy  acid  is  formed.  This  is  one  of  the  most 
important  proofs  that  the  course  of  the  reaction  is  as  given. 
Historically  this  reaction  was  first  used  in  the  synthesis 
of  cumarin  by  Perkin.  Later,  cinnamic  acid  and  its  de- 
rivatives became  of  especial  interest  because  of  their  use 
by  Baeyer  in  the  synthesis  of  indigo. 

Knoevenagel  (Ber.  d.  chem.  Ges.,  27,  2345  :  Ann. 
chem.  (L,iebig),28i,  104)  has  recently  discovered  a  new 
method  of  synthesis  in  which  formaldehyde  is  used,  and 
condensation  takes  place  under  the  influence  of  some 
organic  base.  The  mechanism  of  the  reaction  is  not 
clearly  understood. 

A  somewhat  similar  condensation,  but  one  which  does 
not  lead  to  the  formation  of  an  acid,  is  that  of  formalde- 
hyde, with  derivatives  of  benzene  and  its  homologues, 
under  the  influence  of  concentrated  sulphuric  acid. 


ACIDS.  I'Yl 

NO 


2CeHBN02  +  CH2O  =  C6H4—  CH2—  C6H4—  N02+H2O. 
(Schopff  :  Ber.  d.  chem.  Ges.,  27,  2321.) 
IV.  Decomposition  of  Bibasic  Acids.  —  This  method  of 
preparation  is  used  in  connection  with  the  synthesis  by 
condensation  of  derivatives  of  malonic  acid.  In  the  case 
of  acids  where  the  two  carboxyl  groups  are  not  com- 
bined with  the  same  carbon  atom,  a  clean  decomposition 
cannot  usually  be  effected  by  heat  alone.  In  some 
cases,  however,  one  of  the  carboxyls  may  be  removed 
by  heating  the  barium  salt  of  a  bibasic  acid  with  sodium 
methylate  (Mai:  Ber.  d.  chem.  Ges.,  22,  2136). 

The  decomposition  of  oxalic  acid  may  be  considered 
as  a  special  case  under  this  head  : 

CO2H 

|          =  HC02H  +  C02. 
C02H 

The  decomposition  effected  by  heat  alone  is  unsatis- 
factory in  this  case,  also,  and  heating  with  glycerol  is 
practically  used.  The  glycerol  appears  to  form  an  ester, 

OOTTO 
C8H6</QTT\   ,    wTith   the  formic  acid  as  it   is  formed. 

This  ester  then  decomposes   with   the   water  present, 
yielding  formic  acid  and  regenerating  the  glycerol. 

V  .  Prepa  ration  from  Natural  Products  .  —  M  any  aci  ds  ,  as 
stearic,  oleic,  succinic,  benzoic  and  others,  occur  in 
nature  in  the  form  of  esters  or  glucosides,  and  may  be 
obtained  from  these  by  saponification  or  decomposition 
by  acids  or  alkalies. 


12  ORGANIC   CHEMISTRY. 

(C1,H11CO),CaHb+3KOH=3C1,HslC03K+C!,H6(OH), 

Stearin.  Potassium  stearate  +  Glycerol. 

The  preparation  of  acids  by  oxidation  of  other  com- 
pounds has  already  been  referred  to.  Many  other  illus- 
trations of  the  preparation  of  acids  from  natural  products 
might  be  given,  but  most  of  these  are  individual  rather 
than  general,  and  their  discussion  would  be  out  of  place 
here. 


i.  Preparation  of  an  Acid  by  Oxidation  of  an  Alcohol. 

—  Isovaleric  acid  (3-methylbutanoic  acid). 


Literature.  —  Dumas  u.  Stas  :  Ann.  Chem.  (Liebig),  33,  156  ;  35, 
143  ;  Pierre  u.  Puchot  :  Ibid.,  [4],  29,  229  ;  Stalmann  :  Ibid.,  147, 
129  ;  Erlenmeyer  u.  Hell  :  Ibid.,  160,  275  ;  Duclaux  :  Compt. 
Rend.,  105,  171. 

loo  cc.  amyl  alcohol  (3-methyl  butanol)  . 
100  grams  sodium  pyrochromate.1 
200  cc.  water. 

90  cc.  concentrated  sulphuric  acid. 
90  cc.  water. 

In  a  one  liter  flask  place  100  cc.  amyl  alcohol  (fusel 
oil)  ,  loo  grams  of  powdered  sodium  pyrochromate,  and 
200  cc.  of  water.  Place  in  the  mouth  of  the  flask  a  stop- 
per bearing  a  small,  upright  condenser  having  a  rather 
wide  tube.  Add  in  small  portions,  through  the  con- 
denser tube,  a  cooled  mixture  of  90  cc.  of  concen- 

1  The  use  of  sodium  rather  than  potassium  pyrochromate  is  advised  in 
this  and  other  cases  because  of  the  greater  solubility  of  the  salt. 


ACIDS. 


trated  sulphuric  acid  and  90  cc. 
water.  Shake  vigorously  and  take 
care  that  the  addition  of  the  acid  is 
so  regulated  that  the  reaction  does 
not  become  too  violent.  The  flask 
may  be  cooled  occasionally  by  set- 
ting it  in  cold  water,  if  necessary. 

When  the  acid  has  all  been 
added  and  the  mixture  no  longer 
tends  to  grow  warm  when  shaken, 
remove  the  condenser  and  replace 
it  by  a  stopper  bearing  two  glass 
tubes,  one  reaching  nearly  to  the 
bottom  of  the  flask,  and  the  other 
a  short  bent  tube  leading  to  a  con- 
denser ;  or  a  distilling  bulb  may 
be  used  as  shown  in  the  figure  Dis- 
til by  passing  into  the  flask  a  rapid 
current  of  steam.  The  steam  is  best 
generated  in  a  two  quart  tin,  copper,  or  galvanized  iron 
can,  having  a  stopper  bearing  two  tubes,  one  about  a 
meter  long  and  reaching  nearly  to  the  bottom  of  the  can, 
and  one  a  short,  bent  tube  to  carry  away  the  steam. 
The  latter  is  connected  with  the  longer  tube  in  the  flask 
by  means  of  a  rubber  tube.1 

The  oxidation  converts  a  part  of  the  amyl  alcohol  into 
valeric  acid,  which  then  combines  with  another  part  of 
the  alcohol  to  form  an  ester. 

1  For  a  simple  apparatus  for  steam  distillation,  using  a  reversed  conden- 
ser, see  Matthews,  J.  Chem.  Soc.,  71,  318. 


Fig.  i. 


14  ORGANIC    CHEMISTRY. 

The  distillation  should  be  continued  as  long  as  the 
ester  continues  to  come  over.  Separate  the  ester  from 
the  aqueous  solution,  by  means  of  a  separatory  funnel, 
saving  both.  Put  the  ester  into  a  500  cc.  flask  with  60 
cc.  of  the  aqueous  solution  and  30  grams  of  solid  caustic 


Fig.  2. 

soda.  Adjust  an  upright  condenser,  as  before,  and  boil 
gently  for  fifteen  minutes,  placing  the  flask  on  a  thin 
asbestos  board  or  on  a  wire  gauze  covered  with  a  thin 
sheet  of  asbestos  paper.  Then  add  the  remainder  of 
the  aqueous  solution,  which  contains  some  valeric  acid, 
and  distil,  either  directly  or  with  water  vapor,  as  long  as 
amyl  alcohol  conies  over.  The  amyl  alcohol,  which  is 


ACIDS.  15 

recovered,  may  be  saved  for  use  in  a  new  oxidation.  Con- 
centrate the  residue  in  the  distilling  flask  to  about  100 
cc.  by  evaporation  in  a  porcelain  dish.  Transfer  to  a 
flask,  cool,  and  add  50  cc.  of  dilute  sulphuric  acid  (i  :  i 
by  volume).  Separate  the  valeric  acid  by  means  of  a 
separate ry  funnel,  drawing  off  the  solution  below  and 
pouring  the  acid  out  of  the  top  of  the  funnel  into  a  dry,  50 


Fig.  3- 

cc.  flask.  ,  Add  5  grams  of  fused  calcium  chloride,  stop- 
per loosely  and  warm  for  ten  minutes  on  a  water-bath. 
Cool,  pour  off  the  acid  into  a  small  distilling  bulb  and 
distil,  using  a  thermometer  and  a  condenser  consisting 
of  a  glass  tube  30  cm.  long  and  i  cm.  in  diameter. 
Collect  in  dry  test-tubes  the  fractions  :  below  168°,  168°- 
178°  and  1 78°- 1 90°.  Clean  the  distilling  bulb  and  put  in 
the  low-boiling  fraction  and  distil  till  the  thermometer 
reaches  170°,  add  the  second  fraction  and  distil  into  the 
same  receiver  till  the  thermometer  again  reaches  170°, 
then  into  the  second  receiver.  Establish  two  or  three 


1 6  ORGANIC   CHEMISTRY. 

new  fractions,  according  to  the  rate  at  which  the  ther- 
mometer rises  as  the  acid  comes  over,  the  object  being 
to  obtain  as  large  a  fraction  as  possible  within  an  inter- 
val of  one  or  two  degrees  on  each  side  of  what  appears  to 
be  the  true  boiling-point  of  the  acid.  The  fractional  dis- 
tillation should  be  repeated  till  a  main  fraction  is  ob- 
tained boiling,  in  this  case,  within  an  interval  of  one 
degree.  Yield  about  22  grams. 

To  find  the  true  boiling-point  a  correction  must 
usually  be  applied  to  the  temperature  as  registered.  If 
the  thermometer  is  accurate,  and  has  been  recently  tested 
and  found  accurate  at  its  zero  point  and  boiling-point, 
the  formula,  N(t — /')  0.000154,  will  give  a  close  approxi- 
mation to  the  correction  which  must  be  added  to  the 
temperature  as  read.  N  is  the  number  of  degrees  on 
the  stem  of  the  thermometer  which  are  below  the  tem- 
perature read,  t  is  the  observed  temperature,  and  /'  the 
average  temperature  of  the  stem.  0.000154  is  the  ap- 
parent coefficient  of  expansion  for  mercury  in  glass. 
Another  method,  and  usually  a  better  one,  is  to  deter- 
mine the  boiling-point  of  some  pure  substance,  which 
boils  at  nearly  the  same  temperature,  using  the  same 
apparatus  and  thermometer.  Aniline,  which  boils  at 
183.7°,  would  be  suitable  in  the  present  case. 

Other  substances  which  may  be  used  with  advantage 
for  the  same  purpose  are  ethyl  ether,  which  boils  at  34.6°, 
ethylene  bromide,  at  130.3°,  naphthalene,  at  218.1°,  and 
benzophenone,  at  306.1°.  For  the  last  two,  the  boiling- 
points  under  varying  pressures  have  been  accurately  de- 
termined. (Crafts:  Am.  Chem.  J.,  5,  324.) 


ACIDS.  17 

In  case  the  pressure  of  the  air  is  greater  or  less  than 
760  mm.  a  correction  of  o.i °  for  2.7  mm.  difference  of 
pressure  must  be  applied.  For  substances  with  high 
boiling-points  the  correction  appears  to  be  somewhat 
greater,  but  the  difference  is  not  important  for  ordinary 
purposes.  For  benzophenone  it  is  0.65°  for  10  mm. 

Since  ordinary  amyl  alcohol,  or  fusel  oil,  consists  chiefly 

of  3-methylbutanol,  £^8>CHCHaCHaOH,  the   valeric 

acid  obtained  from  it  will  consist  mainly  of  the  acid  cor- 
responding to  this  formula.  Fusel  oil  contains,  how- 
ever, 10  to  20  per  cent,  of  what  is  supposed  to  be  a 

CH3CH 
mixture  of  the  2-methyl  butanols,  ;CHCH2OH, 

CH, 

and  these  will,  of  course,  give  the  corresponding  acids 
by  oxidation.  Hence,  the  valeric  acid  prepared  from 
fusel  oil,  is  probably  a  mixture  of  at  least  two  or 
three  chemical  individuals.  The  perfectly  pure  iso- 
valeric  acid  (3-methyl  butanoic  acid)  can  be  obtained 
by  conversion  of  the  acid  into  the  barium  salt,  crystal- 
lizing the  latter  from  water  and  then  separating  the  acid 
from  the  pure  salt. 

Pure  isovaleric  acid  is  a  colorless  liquid  with  an  un- 
pleasant odor.  It  boils  at  176.3°  and  has  a  specific 
gravity  of  0.931  at  20°.  It  dissolves  in  23.6  parts  of 
water  at  20°,  but  the  addition  of  soluble  salts  causes 
most  of  it  to  separate  from  the  solution.  The  chromic 
acid  mixture  oxidizes  it  to  acetic  acid  and  carbon  diox- 
ide. 


1 8  ORGANIC   CHEMISTRY. 

The  barium  salt  crystallizes  in  small  prisms  or  thin 
leaflets.  The  silver  salt  crystallizes  in  leaflets  soluble 
in  400  parts  of  water  at  20°,  or  in  204  parts  of  water  at 
80°.  The  salts,  when  thrown  on  water,  rotate  rapidly. 
This  is  characteristic  of  the  salts  of  many  of  the  higher 
fatty  acids. 

The  most  serious  objection  to  this  preparation  is  the 
very  unpleasant  odor  accompanying  it.  The  operations 
should  be  conducted  under  a  hood  as  far  as  possible,  and 
care  should  be  taken  to  avoid  contact  of  the  valeric  acid 
with  the  hands  or  clothing. 

2.  Oxidation  of  a  Ketone — Separation  of  Two  Fatty 
Acids. — Propionic  and  butyric  acids,  C2HBCO,H  and 
CSH7CO3H  (propanoic  and  butanoic  acids) . 

Literature.— Papow :  Ann.  Chem.  (Liebig),  145,  283;  161, 
291;  lyiebig:  Ibid.,  71.355;  Fitz  :  Ber.  d.  chem.  Ges.,  n,  46; 
Hecht:  Ann.  Chem.  (Liebig),  209,  319;  Erlenmeyer  u.  Hill: 
Ibid.,  160,  296;  Baeyer :  Ibid.,  278,  101. 

10  grams  normal  butyric  acid  (butanoic  acid) . 

25  grams  quicklime. 

6  grams  dipropylketone  (4  heptanon). 

25  grams  potassium  pyrochromate. 

1 20  cc.  water. 

20  cc.  concentrated  sulphuric  acid. 

Weigh  in  a  small  porcelain  dish  10  grams  of  normal 
butyric  acid.  Add  carefully,  taking  care  that  the  mix- 
ture does  not  become  so  hot  as  to  volatilize  any  appreci- 
able amount  of  the  acid,  25  grams  of  powdered  quick- 
lime. Mix  thoroughly  and  powder  in  a  mortar.  Place 
the  mixture  in  a  50  cc.  flask,  clamp  the  latter  in  a  hori- 


ACIDS.  19 

zontal  position,  and  connect  it  by  means  of  perforated 
cork  stoppers  and  a  bent  glass  tube  with  a  small  con- 
denser. Distil  by  heating  carefully  with  a  free  flame. 
Collect  the  distillate  in  a  small  flask,  add  a  little  dry 
potassium  carbonate  to  remove  a  small  amount  of  acid 
and  water  which  are  present,  weigh,  pour  off  into  a  500 
cc.  flask  and  weigh  again  to  determine  the  amount  of 
crude  ketone  formed.  For  six  grams  of  the  ketone  add 
a  cooled  mixture  of  25  grams  potassium  pyrochromate, 
20  cc.  concentrated  sulphuric  acid  and  120  cc.  of  water, 
using  more  or  less,  according  to  the  amount  of  the 
ketone.  Boil  for  three  hours  on  a  thin  asbestos  plate, 
with  a  reversed  condenser  (Fig.  i).  Transfer  the  mix- 
ture to  a  200  cc.  distilling  bulb  and  distil  in  a  current  of 
steam  (Fig.  2),  collecting  the  distillate  in  successive  por- 
tions of  10,  25,  50,  and  100  cc.  Prepare,  separately,  cal- 
cium salts  of  the  acid  in  the  first  and  last  portions  by 
boiling  for  a  short  time  with  a  small  quantity  of  pure 
calcium  carbonate,  and  filtering.  Concentrate  each 
solution  to  10  cc.  or  less,  and  add  5  cc.  of  a  ten  per  cent, 
solution  of  silver  nitrate.  Filter  off  the  silver  salt,  best 
on  a  small  Witt  plate  (Fig.  5.),  wash,  dry,  and  deter- 
mine the  per  cent,  of  silver  in  each  salt  by  careful  ignition 
in  a  porcelain  crucible. 

The  oxidation  gives,  in  this  case,  a  mixture  of  pro- 
pionic  and  butyric  acids.  On  distilling  the  mixture  in 
a  current  of  steam  the  butyric  acid,  which  is  less  solu- 
ble, comes  over  mainly  in  the  first  portion,  while  the 
propionic  acid  comes  over  afterwards.  A  single  distil- 
lation as  directed  will  usually,  when  but  two  acids  are 


2O  ORGANIC   CHEMISTRY. 

present,  give  a  sufficient  separation  so  that  the  analyses 
of  the  silver  salts  leave  no  question  as  to  the  composi- 
tion of  the  acids. 

Butyric  acid  boils  at  162°,  and  has  a  specific  gravity  of 
0.978  at  o°.  Propionic  acid  boils  at  141°,  and  has  a  spe- 
cific gravity  of  1.013  at  o°. 

100  parts  of  water  dissolve  0.48  parts  of  normal 
silver  butyrate  and  0.836  parts  of  silver  propionate  at 
20°. 

3.  Oxidation  of  a  Cyclic  Ketone.  —  Camphoric  acid, 


Literature.  —  Kosegarten  :  Dissertation,  Gottingen,  1785  ;  Lau- 
rent: Ann.  Chem.  (Laebig),  22,  135;  Wreden  :  Ibid.,  163,  323; 
Maissen  :  Ber.  d.  chem.  Ges.,  13,  1873  ;  Helle  :  Dissertation, 
Bonn,  1893  ;  Noyes  :  Am.  Chem.  J.,  16,  501  ;  Aschan  :  Structur 
und  Stereochemische  Studien  in  der  Campher  Gruppe,  Hel- 
singfors,  1895,  p.  141. 

/CH, 
50  grams  camphor,  C8H   ' 

XCO 

300  cc.  nitric  acid  (1.42). 
200  cc.  water. 

Place  in  a  one  liter  flask  50  grams  of  camphor,  200 
cc.  of  water,  and  300  cc.  of  nitric  acid  (sp.  gr.  1,42). 
Close  the  mouth  of  the  flask  with  a  tube  of  the  form 
shown  in  the  cut,  filled  with  water. 

The  tube  is  easily  made  by  taking  a  tube  40  cm.  long, 
which  will  pass  easily  into  the  neck  of  the  flask,  seal- 
ing it  at  one  end,  and  blowing  a  small  bulb  at  about  10 
cm.  from  the  sealed  end.  Heat  the  mixture  on  a  boil- 


ACIDS. 


21 


Fig.  4. 


ing  water-bath  or  a  steam-bath  for  seventy- 
two  hours.  Cool,  filter  off  the  camphoric 
acid  with  the  pump  on  a  Hirsch  funnel  or  a 
Witt's  plate,  using  an  "  S.  &  S."  hardened 
filter  (Fig.  5).  After  sucking  away  the 
mother-liquors,  stop  the  pump,  add  enough 
water  to  barely  cover  the  acid,  and  suck  off 
again.  In  all  cases  where  the  substance  to 
be  washed  is  appreciably  soluble  this  method 
should  be  employed,  as  bodies  may,  in  this 
way,  be  effectively  washed  by  the  use  of  a 

much  smaller  quantity  of  the  sol- 
vent than  if  the  pump  is  allowed 
to  act  while  the  solvent  is  poured 
over  the  precipitate.  By  washing 
three  or  four  times  in  this  manner 
the  nitric  acid  will  be  almost  com- 
pletely removed,  and  the  camphoric 
acid,  after  drying,  will  be  suffi- 
ciently pure  for  many  purposes,  and 
especially  for  the  preparation  of  the 
anhydride,  as  the  latter  is  easily 
purified  by  crystallization  from  alco- 
hol .  The  acid  will ,  however,  contain 
some  unchanged  camphor  and,  probably,  a  small  amount 

of  camphoraminic  acid,  C8H14<Cpn  TT   2.       If    a  pure 

v_u3ri 

acid  is  desired,  after  washing  once,  transfer  the  acid  to 
a  beaker,  add  150  cc.  of  water  and  60-65  cc-  of  ammo- 
nia (0.96),  enough  to  convert  the  acid  into  the  ammo- 


22  ORGANIC    CHEMISTRY. 

"nium  salt.  Filter  the  cold  solution,  and  add  slowly, 
with  constant  stirring,  to  70  cc.  of  hydrochloric  acid 
(sp.  gr.  i  .  1  1  ,  4  cc.  =  i  gram  HC1)  .  Filter  on  a  plate  and 
wash  with  cold  water.  Yield  about  30  grams  of  pure 
acid. 

The  acid  mother-  liquors,  if  kept  separate  from  the 
washings,  may  be  brought  up  to  a  specific  gravity  of 
1.29  by  the  addition  of  strong  nitric  acid  and  used  for  a 
second,  and  the  mother-liquors  of  that,  for  a  third  oxida- 
tion. The  yield  in  the  later  oxidations  will  be  some- 
what greater.  The  filtrate  from  the  third  oxidation  will 
contain  considerable  amounts  of  camphoronic  acid, 
C6Hn(C02H)8. 

Camphoric  acid  crystallizes  in  leaflets  or  prisms  which 
melt  at  187°.  In  a  ten  per  cent,  alcoholic  solution  it 
shows  a  rotation  of  polarized  light  [#]j  =  +  49-7°>  or 
[«]D  —  -|-  47.8°.  loo  parts  of  water  dissolve  0.625  parts 
of  the  acid  at  12°,  and  8  to  10  parts  at  100°.  On  heating 
alone,  or  with  acetyl  chloride,  or  acetic  anhydride,  it  is 

OO 
converted  into  the  anhydride,  C8H]4<^J:J>O  .       The 

latter  is  converted  by  ammonia  into  the  ammonium  salt 
of  <*-camphoraminic  acid,  C8H14<^pQ  -^TT  ,  which  on 


CO 
heating  gives  an  imide  C.Hi4<^Q>NH.       This   on 

treatment  with  caustic  soda  gives  the  sodium   salt   of 
/?-camphoraminic  acid,  QS^^^PQXT.,?-  .     Hence  the  two 

carboxyls  of  camphoric  acid  are  not  symmetrically  placed 
in  the  molecule. 


ACIDS.  23 

4.  Oxidation  of  a  Homologue  of  Benzene  with  a 
Halogen  Atom  in  the  Side  Chain. — Benzole  acid, 
C.H.CO.H. 

Literature. — Grimaux,  Hauth  :  Bul.soc.chim.,  7,  100  ;  Lunge  : 
Ber.  d.  chem.  Ges.,  10,  1275  ;  Carius  :  Ann.  Chem.  (Liebig),  148, 51 
and  59  ;  Wagner  :  Jsb.  d.  Chem.,  1880,  1289  ;  V.  Meyer;  Ber.  d. 
chem.  Ges.,  24,  4251 ;  Saiidmeyer  :  Ibid.,  17,  2653. 

20  grams  benzyl  chloride. 

46  grams  nitric  acid  (sp.  gr.  1.42). 

55  grams  water. 

Put  into  a  300  cc.  flask  with  a  narrow  neck,  from  which 
the  lip  has  been  cut  off,  so  as  to  leave  the  neck  straight 
to  the  top,  20  grams  of  benzyl  chloride,  46  grams  (32 
cc.)  of  concentrated  nitric  acid,  and  55  cc.  of  water. 
Slip  over  the  neck  of  the  flask  a  short  piece  of  rub- 
ber tubing,  and  pass  through  this  the  tube  of  an  upright 
condenser  of  such  size  as  to  just  pass  easily  into  the 
neck  of  the  flask  (see  32).  By  this  means  a  tight 
joint  is  formed,  and  at  the  same  time  the  vapors  scarcely 
come  in  contact  with  the  rubber.  Place  the  flask  on  a 
wire  gauze  and  boil  gently  for  2  to  3  hours,  or  until  the 
oxides  of  nitrogen  nearly  disappear  within  the  flask,  and 
the  benzoic  acid  formed  largely  sinks  to  the  bottom  of  the 
liquid.  There  is  some  tendency  for  the  liquid  to  boil 
explosively,  but  there  is  less  trouble  from  this  source  if 
a  round-bottomed  flask  is  used,  and  this  is  heated 
directly  over  a  small  flame  which  is  brought  close  to  the 
wire  gauze,  than  if  the  flask  is  heated  on  a  sand  bath  or 
on  an  asbestos  paper. 

Cool,   filter  on  a  plate,   suck  off  the  mother-liquors, 


24  ORGANIC    CHEMISTRY. 

stop  the  pump,  moisten  thoroughly  with  water  and  suck 
off  again.  Dissolve  the  benzoic  acid  in  70  to  80  cc.  of 
sodium  hydroxide  (10  per  cent.),  added  to  alkaline  reac- 
tion, filter  on  a  plain  filter,  or  pour  off  from  any  benzyl 
chloride  which  remains  undissolved,  put  the  solution  in 
a  flask  or  large  beaker  and  pass  through  it  a  rapid 
current  of  steam  till  the  vapors  no  longer  smell  of  ben- 
zyl chloride.  Precipitate  the  benzoic  acid  again  by 
adding  1 8  to  20  cc.  of  concentrated  hydrochloric  acid. 
Cool  thoroughly,  filter  on  a  plate,  and  wash  once.  Crys- 
tallize from  a  mixture  of  30  cc.  of  alcohol  with  10  to  15 
cc.  of  water. 

The  benzoic  acid  prepared  in  this  way  retains  a  little 
chlorbenzoic  acid  from  which  it  appears  to  be  nearly  or 
quite  impossible  to  free  it.  This  can  be  detected  by 
heating  a  little  of  the  acid,  mixed  with  sodium  carbon- 
ate, on  platinum  foil  till  it  chars,  adding  a  little  potas- 
sium nitrate  and  heating  again  till  white,  dissolving 
the  residue  in  water  and  dilute  nitric  acid,  and  adding 
silver  nitrate.  Yield  13  to  15  grams. 

Benzoic  acid  crystallizes  in  needles  or  leaflets  which 
melt  at  121.4°.  It  boils  at  249°.  TOO  parts  water  dis- 
solve 0.27  part  of  the  acid  at  18°,  and  2.19  parts  at  75°. 
An  impure  acid  is  more  easily  soluble.  It  is  soluble  in 
about  3  parts  of  strong  alcohol  at  15°.  It  is  easily  vola- 
tile with  water  vapor.  The  vapors  of  the  acid  produce 
a  coughing  sensation. 

5.  Oxidation  of  a  Side  Chain  of  a  Hydrocarbon  De- 
rivative.— Ortho-  and  para-nitrobenzoic  acids, 


ACIDS.  25 

Literature. — Beilstein  :  Ann.  Chem.  (Liebig),  133,  41  ;  137, 
302  ;  Hofmann  :  Ibid.,  97»  207  ;  Weith  :  Ber.  d.  chem.  Ges.,  7,  1057  ; 
Monnet,  Reverdin,  Nolting :  Ibid.,  12,  443 ;  Nolting,  Witt : 
Ibid.,  18,  1336. 

40  grams  toluene. 

50  cc.  sulphuric  acid  (1.84). 

30  cc.  nitric  acid  (1.42). 

Place  in  a  300  cc.  flask,  40  grams  (46  cc.)  of  toluene 
and  add  in  small  portions  a  cooled  mixture  of  50  cc.  of 
concentrated  sulphuric  acid,  and  30  cc.  of  nitric  acid 
(1.42).  Shake  vigorously  and  cool  after  each  addition, 
taking  care  that  the  temperature  does  not  rise 
above  30°.  After  the  acid  has  all  been  added, 
shake  vigorously  for  ten  minutes,  keeping  the 
temperature  down  as  before.  Pour  into  about 
700  cc.  of  water.  The  nitrotoluene  will  now 
sink  to  the  bottom.  Separate  from  the  acid 
liquid  with  a  separatory  funnel,  and  wash  by 
shaking  the  nitrotoluene  again  with  about  100 
cc.  water.  In  this  and  all  similar  cases  where 
a  heavy  liquid  is  to  be  separated  from  water,  it 
is  best  to  use  a  flask  or  separatory  funnel  of 
such  size  that  the  mixture  will  fill  it  nearly  to 
the  top,  as  otherwise  a  considerable  amount  of  the  heavy 
liquid  may  remain  floating  on  top  of  the  water.  Separate 
the  nitrotoluene  as  completely  as  possible  from  the  water, 
put  it  in  a  small  flask,  add  10  grams  of  fused,  granulated 
calcium  chloride,  and  warm  on  a  water-bath  with  the 
flask  covered  with  a  watch-glass  for  half  an  hour,  or 
allow  it  to  stand  over  night.  Pour  the  nitrotoluene  off 


26 


ORGANIC   CHEMISTRY. 


into  a  distilling  bulb.  Distil,  using  a  glass  tube  as  a 
condenser  (see  Fig.  3).  The  portion  distilling  below 
200°  consists  principally  of  unchanged  toluene,  and  may 
be  saved.  That  distilling  between  2oo°-24O°  consists 
chiefly  of  ortho-  and  paranitro toluene,  while  that  boiling 
above  250°  consists  chiefly  of  dinitrotoluene.  Ortho- 
nitrotoluene  boils  at  220°  and  melts  at  — 10.5°.  Para- 
nitrotoluene  boils  at  239°  and  melts  at  54°.  The  two  can 
be  partially  separated  by  fractional  distillation,  and  the 
para  compound  can  be  obtained  pure  by  crystallization 
from  alcohol.  For  the  remainder  of  this  preparation  the 
mixture  boiling  from  2OO°-24O°  may  be  used. 
15  grams  mixed  nitrotoluenes. 
100  cc.  water. 

10  cc.  sodium  hydroxide  (10  per  cent). 
35  grams  potassium  permanganate. 
350  cc.  water. 

Arrange  a  one  liter  flask  with  an  up- 
right condenser,  a  bent  thistle  tube,  and 
a  bent  tube  to  convey  steam  to  the  bot- 
tom of  the  flask,  as  indicated  in  the  fig- 
ure. (See  Fig.  7). 

Place  in  the  flask  15  grams  of  the  mixed 
nitrotoluenes,  100  cc.  of  water,  and  10  cc. 
of  a  10  per  cent,  solution  of  sodium  hy- 
droxide. Add  about  50  cc.  of  a  warm 
10  per  cent,  solution  of  potassium  per- 
manganate. Pass  in  a  current  of  steam 
rapidly  till  the  solution  boils,  and  then 
Fig.  7.  just  fast  enough  to  keep  the  contents  of 


ACIDS.  27 

the  flask  agitated,  and  so  that  a  small  amount  of  steam 
condenses  above.  Add  more  of  the  permanganate  solu- 
tion at  frequent  intervals  till  35  grams  of  the  salt  in  all 
have  been  added.  Continue  the  current  of  steam  until 
the  pink  color  of  the  permanganate  disappears,  or  till  the 
drops  of  nitrotoluene  cease  to  appear  in  the  condenser.  If 
unreduced  permanganate  is  still  present,  add  a  few  drops 
of  alcohol,  and  shake  to  reduce  it.  Filter  hot,  from  the 
oxides  of  manganese,  on  a  filter  plate  or  Hirsch  funnel, 
and  wash  twice  with  water.  Concentrate  the  filtrate  to 
about  40  cc. ,  and  precipitate  the  mixed  ortho-  and  parani- 
trobenzoic  acids  with  25  cc.  of  concentrated  hydrochloric 
acid.  Cool  very  thoroughly,  filter  on  a -plate,  and  wash 
twice  with  a  very  small  amount  of  cold  water,  sucking  off 
the  mother- liquors  thoroughly  each  time  (see  3»  p.  21). 
Convert  into  the  barium  salts  by  boiling  with  about  12 
grams  of  barium  carbonate  and  200  cc.  of  water.  Filter 
hot  and  cool  the  filtrate.  A  considerable  portion  of  the  ba- 
rium salt  of  the  para  acid  will  separate.  Filter,  wash  once 
with  cold  water  and  concentrate  the  filtrate  and  washings 
to  a  very  small  volume.  Cool  quickly,  and  filter  at  once  on 
a  plate.  Moisten  the  residue  several  times  with  a  small 
amount  of  cold  water  and  suck  off.  Concentrate  the  filtrate 
and  washings,  and  crystallize  the  ortho  salt  by  allowing 
the  cold,  concentrated  solution  to  stand  for  some  time. 
Recrystallize  both  the  ortho  and  para  salts  from  hot 
water,  saving  the  mother-liquors  and  working  them  up  in 
such  a  manner  as  to  secure  as  large  an  amount  as  possi- 
ble of  each  salt  in  a  pure  condition. 

The  separation  of  two  substances  by  crystallization  is 


28  ORGANIC   CHEMISTRY. 

a  problem  which  frequently  presents  itself  in  organic 
chemistry,  and  it  frequently  requires  very  careful  work 
and  good  judgment  to  secure  both  substances  in  pure 
condition  without  serious  loss  of  material.  As  the 
substance  which  is  present  in  least  amount,  or  which  is 
most  easily  soluble,  is  liable  to  form  supersaturated 
solutions,  it  is  usually  advisable  to  filter  off  a  substance 
which  has  crystallized  as  soon  as  its  separation  from  the 
solution  appears  to  be  practically  complete.  The  separa- 
tion can  frequently  be  hastened  by  vigorous  stirring, 
and  by  the  addition  of  a  fragment  of  the  pure  substance, 
when  crystals  are  slow  in  starting.  Occasionally,  how- 
ever, a  substance  may  form  crystals  sufficiently  large  to 
be  separated  mechanically  from  others  with  which  they 
are  mixed.  In  such  cases  the  crystallizations  must  be 
allowed  to  proceed  slowly  and  undisturbed,  and  it 
may  be  well  to  allow  the  solution  to  evaporate  slowly 
at  ordinary  temperatures,  or  in  vacua  over  sulphuric 
acid.  L,arge  crystals  of  the  barium  salt  of  orthonitro- 
benzoic  acid  may  be  obtained  in  this  way. 

Crusts  which  separate  on  the  walls  of  a  dish  or  beaker 
during  evaporation,  usually  consist  of  a  mixture,  and 
should  be  brought  back  into  the  solution  and  redis- 
solved  by  heating  before  the  latter  is  cooled  for  crystal- 
lization. 

In  using  a  solvent,  a  very  common  mistake  is  to  use 
too  large  an  amount.  A  small  amount  should  always  be 
added  at  first,  unless  the  properties  of  the  substance  are 
familiar,  and  then  more,  if  the  substance  cannot  be 
brought  into  solution. 


ACIDS.  29 

With  substances  which  separate  very  easily  on  cool- 
ing the  solution,  the  opposite  mistake  may  be  made,  if 
the  solution  requires  filtration.  In  such  cases,  the  sub- 
stance should  be  taken  only  in  such  amount  as  will  dis- 
solve very  easily  in  the  amount  of  the  solvent  used,  and 
care  must  be  taken  to  prevent  the  crystallization  of  the 
substance  on  the  filter,  either  by  the  use  of  a  plate,  (not 
a  Hirsch  funnel) ,  and  pouring  only  as  fast  as  the  solution 
runs  through  the  filter,  or  by  the  use  of  a  hot  water  fun- 
nel. The  latter  is  rarely  necessary,  if  the  chemist  has 
acquired  the  necessary  experience,  except  in  cases  where 
a  precipitate  clogs  the  filter  badly. 

When  alcohol  is  used  as  a  solvent,  the  yield  of  crys- 
tals may,  sometimes,  be  increased  by  adding  some  water 
to  the  solution  before  it  cools.  When  the  impurities  are 
soluble  in  dilute  alcohol,  this  may  be  used  with  advan- 
tage instead  of  pure  alcohol  to  wash  the  crystals. 

It  should  be  remembered  that  strong  alcohol  is  not  a 
suitable  solvent  for  some  acids  and  some  nitro-phenols 
because  of  the  ease  with  which  they  form  esters. 

Crystallization  is  the  most  valuble  means  in  the  hands 
of  the  chemist  for  obtaining  pure  substances.  When  it 
can  be  applied,  it  almost  always  gives  purer  substances 
than  fractional  distillation.  In  working  with  new  sub- 
stances, success  very  often  depends  largely  on  the  choice 
and  use  of  proper  solvents,  and  it  is  a  matter  to  which 
the  beginner  should  give  very  careful  attention.  In 
working  with  new  bodies  valuable  hints  can  almost 
always  be  obtained  by  learning  from  text-books  or 
chemical  journals  the  conduct  of  closely  related  bodies 
which  have  been  previously  known. 


30  ORGANIC    CHEMISTRY. 

Orthonitrobenzoic  acid  crystallizes  in  colorless,  tri- 
clinic  prisms,  which  have  a  sweet  taste,  melt  at  147°,  and 
dissolve  in  164  parts  of  water  at  16.5°. 

Paranitrobenzoic  acid  crystallizes  in  yellow  leaflets, 
which  melt  at  240°,  and  dissolve  in  1200  parts  of  water 
at  17°,  or  in  140  parts  at  100°. 

The  barium  salt  of  the  ortho  acid  crystallizes  with  3 
molecules  of  water,  in  yellow,  triclinic  crystals,  which  are 
easily  soluble  in  water. 

The  barium  salt  of  the  para  acid  crystallizes  with  5 
molecules  of  water,  in  yellow,  monoclinic  prisms,  soluble 
in  250  parts  of  cold,  and  8  parts  of  hot  water. 

The   purity   of   solid   substances  is,   in  many  cases, 


most  easily  tested  by  means  of  the  melting-point.  For 
this  purpose  the  substance  must  be  perfectly  dry.  The 
drying  can  be  effected  by  allowing  the  body  to  lie  for  a 
sufficient  length  of  time  on  filter  paper,  or  on  clean  por- 
ous porcelain,  best  over  sulphuric  acid  in  vacua. 

A  lot  of  capillary  tubes  for  the  determination  of  melting 
points  may  be  prepared  by  taking  a  soft  glass  tube  with  not 
too  thin  walls,  4  to  5  mm.  in  external  diameter,  and 
drawing  it  out  as  indicated  above.  (See  Fig.  8.) 

The  tube  is  then  sealed  off  near  each  bulb,  and  the 
closed  tubes  kept  till  needed.  For  use,  the  bulb  is  cut 
in  two  by  scratching  with  a  file  and  breaking.  The 
finely  powdered  substance  is  put  into  the  wide  end  of 


ACIDS.  31 

the  tube  and  shaken  down,  or  pushed  down  to 
the  point  with  a  clean  platinum  wire.  For  a 
melting-point  bath  the  best  for  general  use  is  a 
round-bottomed,  75  cc.  flask,  with  a  rather  long 
neck.  In  the  mouth  is  placed  a  stopper,  perfo- 
rated so  that  the  thermometer  will  pass  easily 
through  it,  and  be  held  in  place  by  a  small 
wooden  wedge,  e.g.,  a  match  stick.  Through 
the  side  of  the  cork  passes  a  small  platinum  wire 
with  loops,  as  indicated  in  the  figure.  (See  Fig. 
9.)  If  moistened  with  the  sulphuric  acid,  the 
tube  will  adhere  to  the  thermometer  by  capillary 
attraction,  but  such  an  arrangement  is  less  se- 
cure, g.  9- 
The  part  of  the  capillary  tube  con- 
taining the  substance  should  lie  in 
contact  with  the  bulb  of  the  ther- 
mometer. The  bath  may  be  heated 
rapidly  with  a  free  flame  till  the  tem- 
perature approaches  the  melting-point, 
and  then  very  slowly.  In  case  of 
bodies  which  decompose  at  or  near 
their  melting-points,  the  thermometer 
and  the  tube  should  be  brought  as 
quickly  as  possible,  without  danger 
Fig.  10.  of  breaking  the  thermometer,  into  the 
hot  bath  and  the  latter  brought  quickly  to  the  melting- 
point.  The  result,  in  such  cases,  cannot  be  very  accu- 
rate. 

When,  as  is  usually  the  case,  the  stem  of  the  ther- 


32  ORGANIC    CHEMISTRY. 

mometer  is  not  immersed  in  the  sulphuric  acid  to  the 
point  to  which  the  mercury  rises,  a  correction  similar  to 
that  for  boiling-points  must  be  applied.  (See  i,  p.  16.) 
In  general,  a  sharp  melting-point,  within  an  interval 
of  one  degree,  at  most,  is  characteristic  of  a  pure  sub- 
stance, while  impure  substances  melt  indefinitely. 

6,  Preparation  of  a  Cyanide  and  Acid  from  a  Halo- 
gen Derivative  of  a  Hydrocarbon. — Succinic  acid, 
CH,— C02H 

CH3— COaH. 

Literature. — Simpson:  Ann.  Chem.  (L,iebig),  118,  374;  xax, 
154;  Nevole  u.  Tscherniak :  Bui.  soc.  chim.,  30,  101  ;  Fau- 
connier  :  Ibid,  50,  214  ;  Brown,  Walker  :  Chem.  News,  66,  91  ; 
Ann.  Chem.  (Iviebig),  261,115;  Ljebig:  Ibid,  70,  104,  363; 
Konig:  Ber.  d.  chem.  Ges.,  15,  172. 

50  grams  ethylene  bromide. 
100  cc.  alcohol. 

34  grams  potassium  cyanide. 

35  cc.  water. 

40  grams  potassium  hydroxide. 

65  cc.  concentrated  hydrochloric  acid. 

Place  in  a  300  cc.  flask  50  grams  of  ethylene  bromide 
and  loo  cc.  of  alcohol.  Connect  with  an  upright  con- 
denser, heat  to  boiling  on  a  water-bath,  and  drop  into 
the  solution  slowly  from  a  drop  funnel  placed  in  the  top 
of  the  condenser,  a  solution  of  34  grams  of  potassium 
cyanide  in  35  cc.  of  water.  After  the  solution  has  all 
been  added,  boil  on  the  water-bath  for  an  hour  and  a 
half.  Cool,  and  pour  off  from  the  potassium  bromide 


ACIDS.  33 

into  a  flask  containing  40  grams  of  solid  potassium 
hydroxide,  cooling,  if  necessary,  to  prevent  too  violent  a 
reaction  at  first.  Rinse  the  residue  of  potassium  bro- 
mide twice  with  a  small  amount  of  alcohol,  adding  the 
rinsings  to  the  main  portion.  Boil  with  an  upright 
condenser  for  two  hours.  Pour  the  contents  of  the  flask 
into  a  porcelain  dish,  and  evaporate  on  the  water-bath 
till  the  alcohol  is  entirely  removed.  Add  fifty  cc.  of 
water,  and  40  cc.  of  concentrated  hydrochloric  acid,  and 
filter.  To  the  filtrate  add  25  cc.  more  of  concentrated 
hydrochloric  acid,  cool  very  thoroughly,  filter  off  the 
succinic  acid,  and  crystallize  it  from  hot  water.  The 
yield  is  poor. 

Succinic  acid  crystallizes  from  water  in  tabular  crys- 
tals. It  melts  at  182°.  If  heated  above  its  melting- 
point,  it  is  converted  into  the  anhydride.  100  parts  of 
water  at  o°  dissolve  2.8,  at  20°  6.9  parts,  at  50°  24.4 
parts  of  the  acid.  100  parts  of  alcohol  at  12° dissolve  7.5 
parts,  and  100  parts  of  ether  1.26  parts. 

Kthylene  cyanide  is  present  in  the  above  alcoholic  so- 
lution and  can  be  obtained  from  it  as  follows  :  Pour  the 
solution  off  from  the  potassium  bromide  into  a  300  cc. 
distilling  bulb,  rinse  as  before,  and  distil  off  as  much  of 
the  alcohol  as  possible  on  the  water-bath.  Transfer  to 
a  100  cc.  bulb,  fitted  with  a  thermometer,  capillary  tube, 
and  receiving  bulb,  as  indicated  in  Fig.  12,  p.  46.  Distil 
on  the  water-bath  under  diminished  pressure  as  long  as 
alcohol  or  water  comes  over.  Then  change  the  receiver 
and  distil  carefully  over  a  free  flame,  or  in  an  oil  bath, 
with  the  pressure  as  low  as  possible. 


34  ORGANIC   CHKMISTRY. 

Kthylene  cyanide  boils,  under  10  mm.  pressure  at 
147°,  under  760  mm.  pressure  at  26^-26^°,  with  partial 
decomposition.  It  melts  at  54°, 

7.  Preparation  of  an  Ester  of  a  Bibasic  Acid  from  a 
Halogen  Derivative  of  an  Acid.  —  Malonic  ester, 


Literature.  —  Dessaignes  :  Ann.  Chem.  (L,iebig),  107,  251  ; 
Kolbe  and  Miiller:  Ibid,  131,  348,  350;  Finckelstein  :  Ibid,  133, 
350;  Conrad:  Ibid,  204,  126;  Claisen  and  Venable  :  Ibid,  218, 
131.  Kolbe  and  Miiller  :  J.  Chem.  Soc.,  17,  (1864)  109;  Noyes  : 
J.  Am.  Chem.  Soc.,  18,  1105  (1896). 

50  grams  monochloracetic  acid. 

45  grams  acid  sodium  carbonate. 

TOO  cc.  water. 

40  grams  potassium  cyanide. 

100  cc.  alcohol. 

80  cc.  concentrated  sulphuric  acid. 

Put  50  grams  of  monochloracetic  acid  into  a  porcelain 
dish  20  cm.  in  diameter.  Add  100  cc.  of  water,  and  45 
grams  of  acid  sodium  carbonate.  Warm,  stirring  with  a 
thermometer,  till  a  temperature  of  5o°-6o°  is  reached,  and 
the  effervescence  has  ceased.  Place  the  dish  on  a  sheet 
of  asbestos  paper  on  a  tripod,  in  a  hood  with  a  good 
draught.  Add  40  grams  of  powdered  potassium  cya- 
nide, and  stir  vigorously  with  the  thermometer.  Warm 
only  very  gently  till  the  reaction,  which  takes  place 
with  considerable  evolution  of  heat  and  spontaneous 
boiling  of  the  solution,  is  complete.  Then  raise  the 
flame  and  evaporate  rapidly,  stirring  constantly  with  the 


ACIDS.  35 

thermometer  till  a  temperature  of  130°  is  reached.  Dur- 
ing this  part  of  the  operation  keep  the  window  glass  of 
the  hood  between  the  dish  and  the  face,  and  cover  the 
hand  with  a  towel  or  glove  to  protect  it  from  the  par- 
ticles of  the  mixture  which  are  thrown  out.  Remove 
the  dish  from  the  flame,  and  continue  to  stir  till  the  mass 
is  cold.  Transfer  at  once  to  a  500  cc.  flask,  as  the  mass 
is  very  hygroscopic.  Connect  the  flask  with  an  upright 
condenser  (seei»p.  13).  Add  20 cc.  of  alcohol  and  then,  in 
small  portions,  through  the  condenser,  a  cooled  mixture 
of  80  cc.  of  alcohol  with  80  cc.  of  concentrated  sulphuric 
acid.  After  each  addition,  mix  the  contents  of  the  flask 
as  thoroughly  as  possible  by  shaking.  When  all  of  the 
mixture  has  been  added,  shake  till  the  whole  is  thor- 
oughly mixed,  and  then  heat  on  the  water-bath  for  an 
hour.  Cool,  add  150  cc.  of  cold  water,  and  shake  thor- 
oughly. Filter  on  a  Hirsch  funnel  or  plate,  and  suck 
the  liquid  through  as  completely  as  possible.  Stop  the 
pump,  moisten  the  salt  with  ether;  after  a  minute  or  so 
draw  this  through,  and  repeat  twice.  Transfer  the  con- 
tents of  the  filtering  flask  to  a  separatory  funnel  and 
draw  off  the  salt  solution  below.  Add  a  small  amount 
of  a  strong  solution  of  sodium  carbonate,  and  shake 
carefully  with  the  funnel  open  at  the  top  to  allow  the 
carbon  dioxide  to  escape.  When  enough  of  the  solution 
has  been  added  to  neutralize  the  free  acid,  insert  the 
stopper  and  shake  more  vigorously,  holding  the  stopper 
firmly  in  place,  and  after  each  shaking  turning  the  fun- 
nel bottom-side  up  and  opening  the  stop-cock  to  re- 
lieve the  pressure.  Allow  the  two  layers  to  separate  as 


36  ORGANIC   CHEMISTRY. 

completely  as  possible,  draw  off  the  aqueous  solution 
below,  allowing  it  to  run  into  the  first  acid  solution. 
Transfer  the  ethereal  solution  of  the  malonic  ester  to  a 
distilling  bulb.  Distil  off  the  ether  on  a  water-bath, 
using  a  condenser,  then  put  in  the  mouth  of  the  bulb  a 
rubber  stopper  bearing  a  tube  drawn  out  below  to  a  fine 
capillary,  which  reaches  nearly  to  the  bottom  of  the 
bulb,  and  attach  a  second  bulb  to  the  side  tube  (see  Fig. 
12,  p.  46,  but  omit  the  thermometer).  Heat  in  the  water- 
bath  and  reduce  the  pressure  to  50  mm. ,  or  less,  for  fifteen 
minutes.  This  method  of  drying  substances  which  boil 
above  190°  is  usually  quicker  and  more  satisfactory  than 
the  use  of  calcium  chloride  or  other  drying  agents. 
Malonic  ester  may  also  be  dried  with  advantage  by  al- 
lowing it  to  stand  in  a  crystallizing  dish  in  a  vacuum 
desiccator  for  twenty- four  hours. 

After  drying,  distil  with  a  thermometer  and  condens- 
ing tube  (see  i,  p.  15) .  Very  little  passes  over  below  190°, 
and  that  boiling  from  i9o°-2OO°  will  be  very  nearly  pure 
malonic  ester.  If  a  very  pure  ester  is  desired,  it  may  be 
distilled  again,  and  only  the  portion  boiling  within  one 
degree  of  the  true  boiling-point  taken.  Yield,  45  grams. 

The  sodium  carbonate  solution  contains  some  of  the  acid 
ester.  If  this  solution  is  added  to  the  first  acid  solu- 
tion, the  acid  ester  separates  with  some  ether.  The 
ethereal  solution  may  be  separated,  the  ether  evaporated 
at  a  gentle  heat,  and  the  residue  added  to  the  contents 
of  the  flask,  in  which  a  second  saponification  of  the 
cyanacetate  is  to  be  effected.  This  will  increase  the 
yield  to  50  grams. 


ACIDS.  37 

Malonic  ester  is  a  colorless  liquid  which  boils  at  198°, 
and  has  a  specific  gravity  of  1.061  at  15°.  It  is  decom- 
posed on  heating  to  150°  with  water,  giving  acetic  ester, 
carbon  dioxide,  and  alcohol.  (For  the  conduct  of  ma- 
Ionic  ester  toward  sodium  ethylate  and  its  use  in  syn- 
theses, see  p.  8.) 

If  it  is  desired  to  prepare  malonic  acid,  after  adding 
the  potassium  cyanide  as  directed  above,  continue  to 
heat  gently  for  half  an  hour,  then  add  120  cc.  of  a  strong 
solution  of  sodium  hydroxide  (3  cc.  =  i  gram  NaOH), 
and  continue  to  heat,  replacing  the  water  which  evapo- 
rates, as  long  as  the  evolution  of  ammonia  continues, 
usually  about  an  hour.  Add  carefully  68  cc.  of  hydro- 
chloric acid  (4  cc.  =  i  gram  HC1),  and  a  solution  of  70 
grams  of  calcium  chloride.  Filter,  wash  with  cold 
water,  and  dry  at  100°.  The  calcium  malonate  retains 
two  molecules  of  water.  To  obtain  the  free  acid  the  salt 
is  decomposed  by  warming  with  the  calculated  amount 
of  a  strong  solution  of  oxalic  acid,  filtering  from  the  cal- 
cium oxalate,  and  evaporating  to  crystallization.  Ma- 
lonic acid  melts  at  134°  and  dissolves  in  about  two-thirds 
of  its  weight  of  water  at  16°.  At  140°- 150°  it  decom- 
poses into  carbon  dioxide  and  acetic  acid,  a  reaction 
characteristic  of  acids  having  two  carboxyls  combined 
with  one  carbon  atom. 

The  calcium  salt  is  almost  insoluble  in  cold  water. 

8.  Preparation  of  an  o'-Hydroxy  Acid  from  an  Al- 
dehyde, through  the  Cyanhydrin. — Mandelic  acid, 

/OH 

C6H5C— CO2H     (phenethylolic  acid). 
\H   ' 


38  ORGANIC    CHEMISTRY. 

Literature. — Winckler:  Ann.  Chetn.  (Liebig),  18,310  ;  Spiegel: 
Ber.  d.  chem.  Ges.,  14,  239;  Engler,  Wohrle  :  Ibid,  20,  2202; 
Wallach  :  Ann.  Chem.  (I^iebig),  193,  38;  Luginin  u.  Naquet : 
Ibid,  139,  299  ;  Miiller :  Ber.  d.  chem.  Ges.,  4.  980. 

20  grams  benzaldehyde. 

13  grams  potassium  cyanide. 

15.3  cc.  hydrochloric  acid  (sp.  gr.  1.19). 

Put  into  a  small  flask  13  grams  (i  mol.)  oipure  potas- 
sium cyanide,  and  20  grams  (i  mol.)  of  freshly  distilled 
benzaldehyde.  Place  the  flask  in  ice-water,  and  drop  in 
slowly  from  a  burette  7  grams  (i  mol.)  of  hydrochloric 
acid.  This  will  be  14.3  cc.  of  an  acid  of  sp.  gr.  1.20,  or 
15.3  cc.  of  an  acid  of  sp.  gr.  1.19.  During  the  addition 
of  the  acid  shake  frequently,  and  allow  the  mixture  to 
stand  for  one  hour  after  all  has  been  added.  Then  pour 
into  150  cc.  of  cold  water.  Separate  the  cyanhydrin 
from  the  solution,  and  wash  twice  with  water  (see  5,  p.  25). 
Transfer  the  nitrile  to  a  porcelain  dish,  add  50  cc.  of 
concentrated  hydrochloric  acid,  and  evaporate  on  a 
sand-bath  till  crystals  begin  to  separate  on  the  upper 
surface  of  the  liquid.  Dissolve  the  residue  in  about  100 
cc.  of  warm  water,  filter  from  any  oil  which  remains, 
and  extract  the  mandelic  acid  from  the  filtrate  with  ether. 

In  extracting  with  ether,  especially  when,  as  in  this 
case,  the  substance  to  be  extracted  is  easily  soluble  in 
water,  the  solution  should  be  as  concentrated  as  possi- 
ble. It  is  also  an  advantage,  in  many  cases,  to  add  salt 
or  ammonium  sulphate  to  the  solution  which  is  to  be 
extracted.  This  lessens  the  solubility  of  the  ether  in 
the  solution  and  also  of  the  water  in  the  ether.  In  ex- 


ACIDS.  39 

tracting,  put  the  solution  to  be  extracted  into  a  separa- 
tory  funnel,  which  should  be  chosen  of  such  size  as  to 
be  nearly  filled.  Add,  according  to  the  ease  with  which 
the  substance  is  extracted  from  the  solution  and  accord- 
ing to  the  volume  of  the  latter,  10-50  cc.  of  ether. 
When  a  substance  is  easily  extracted,  use  but  little 
ether ;  if  extracted  with  difficulty,  a  larger  amount;  and 
the  extraction  must,  in  such  a  case,  be  many  times  re- 
peated. These  rules  follow  from  the  law  for  the  divi- 
sion of  a  substance  between  two  immiscible  solvents, 
which  is  that  the  amounts  retained  in  a  unit  volume  of 
each  have  a  fixed  ratio,  independently  of  the  volume  of 
each.  The  ratio  is  called  the  division-coefficient,  and  in 
the  present  case  expresses  the  amount  of  substance  con- 
tained in  TOO  cc.  of  the  aqueous  solution,  divided  by  the 
amount  contained  in  100  cc.  of  the  ethereal  solution. 

Expressed  mathematically,  let 

x0  =  amount  of  substance  present. 

xl  =  amount  of  substance  retained  by  the  water. 

x0 — xl  =  amount  of  substance  retained  by  the  ether. 

k  =  division-coefficient. 

/  =  amount  of  water. 

m  =  amount  of  ether. 

— -  =  concentration  of  the  ethereal  solution. 

m 

-y\==  concentration  of  the  aqueous  solution. 
Then  by  the  definition 

'-5 1-  or  xl  =  kl  — 

Wl  Wl 


40  ORGANIC    CHEMISTRY. 

kl 

or>  *.  =  X^^KT 

m 

and  x — x  —  xn — — : — ^-.. 
0  m  +  kl 

An  examination  of  the  last  expression,  which  gives 
the  amount  of  substance  removed  by  a  single  extrac- 
tion, shows  that  if  k  is  large,  that  is,  if  the  substance  is 
very  soluble  in  water  in  proportion  to  its  solubility  in 
ether,  the  amount  extracted  increases  rapidly  with  the 
amount  of  ether  used,  but  that  several  extractions  must 
be  required.  If  k  is  small,  however,  an  increase  of  m, 
or  the  amount  of  ether,  has  little  effect  on  the  value  of 
the  fraction  and  a  few  extractions  with  a  small  amount 
of  ether  will  suffice. 

In  extracting,  after  adding  the  ether,  the  stop-cock  of 
the  funnel  should  be  inserted  and  held  firmly  in  place 
while  the  contents  are  shaken  vigorously.  Only  when 
there  is  danger  of  forming  an  emulsion  which  will  sepa- 
rate into  layers  with  difficulty,  should  the  agitation  of 
the  liquids  be  more  gentle.  After  shaking,  the  funnel 
should  be  inverted,  and  the  stop-cock  opened  for  a 
moment  to  relieve  any  pressure  due  to  vapor  of  ether. 
The  funnel  is  then  set  upright  and  allowed  to  stand  till 
the  two  layers  separate.  In  case  separation  does  not 
take  place  satisfactorily  it  may  be  necessary  to  add  more 
ether,  or  a  few  drops  of  alcohol.  In  extreme  cases,  fil- 
tration on  a  plate,  or  through  a  tube  containing  some 
cotton,  may  be  necessary.  Occasionally  an  emulsion  can 
be  caused  to  clear  by  connecting  the  funnel  with  the 
pump  and  exhausting  till  the  ether  boils  for  a  short 


ACIDS. 


time.  When  separation  has  taken  place,  the  aqueous 
solution  is  drawn  off  into  a  flask.  It  is  usually  an  ad- 
vantage when  the  solution  has  been  nearly  removed, 
to  give  the  funnel  a  slight  rotary  motion  to  collect  the 
solution  at  the  bottom,  where  it  can  be  drawn  off.  The 
ether  is  then  poured  from  the  top  of  the  funnel  into  a 
flask  or  distilling  bulb,  care  being 
taken  not  to  pour  out  any  drops 
of  the  aqueous  solution  which 
may  remain. 

The  end  of  the  extraction  may 
be  determined  by  taking  a  little 
of  the  ethereal  solution  in  a  dry 
test-tube,  and  evaporating  the 
ether  quickly  by  immersion  in  a 
boiling  water-bath,  and  finally 
inverting  the  tube  to  allow  the 
vapor  of  ether  to  fall  out. 

In  working  with  small  quan- 
tities, extractions  may  sometimes 
be  made  with  advantage  in  a  test-tube  and  the  ethereal 
solution  drawn  off  with  a  small  pipette,  suction  being  ap- 
plied to  the  latter  through  a  rubber  tube  long  enough  for 
the  eye  to  be  brought  into  a  position  to  see  the  liquid .  It  is 
an  advantage  to  draw  the  pipette  out  to  a  capillary  below. 

The  ethereal  solution  of  the  mandelic  acid  should  be 
distilled  and  the  residue  dried  on  the  water-bath  in  a 
watch-glass  or  porcelain  dish.  The  acid,  which  crystal- 
lizes on  cooling,  may  be  recrystallized  from  benzene. 
Yield  10  to  15  grams. 


Fig.  ii. 


42  ORGANIC    CHEMISTRY. 

Mandelic  acid  crystallizes  from  water  in  large  rhombic 
crystals,  and  from  benzene  in  leaflets,  which  melt  at  1 18°. 
100  parts  of  water  at  20°  dissolve  15.97  parts  of  the  acid. 

As  with  all  substances  prepared  by  synthesis  from  in- 
active bodies,  it  is  inactive,  but,  as  it  contains  an  asym- 
metric carbon  atom,  it  may  be  separated  into  two  active 
forms.  The  separation  may  be  effected  by  the  crystalli- 
zation of  the  cinchonine  salt,  or  by  the  growth  of  Penicil- 
lium  Glaucum,  or  Saccharomyces  ellipso'ideus,  in  a  solu- 
tion of  the  ammonium  salt.  The  former  destroys  the 
laevo  form,  the  latter  the  dextro  form. 

9.  Preparation  of  an  Acid  from  an  Amine  through 

the  Diazo  Compound.— Paratoluic  acid,  c«H4<co  H(  *  \ 
Literature.— Spica  and  Paternd  :  Ber.  d.  chem.   Ges.,  8,  441  ; 
Sandmeyer  :    Ibid,  17,  1633,  2653  ;   18,  1492 ;  Baeyer  and  Tutein  : 
Ibid,   22,  2178  ;  Herb  :  Ann.  Chem.  (Liebig;,  258,  8. 

21.4  grams  paratoluidine. 

39  grams  concentrated  hydrochloric  acid. 

150  cc.  water. 

50  grams  ice. 

14  grams  sodium  nitrite. 

70  cc.  water. 

55  grams  potassium  cyanide. 

100  cc.  water. 

50  grams  copper  sulphate. 

100  cc.  water. 

10  grams  tolunitrile. 

30  cc.  concentrated  sulphuric  acid, 

20  cc.  water. 


ACIDS.  43 

In  a  one  liter  flask  dissolve  50  grams  of  copper  sul- 
phate in  100  cc.  of  hot  water.  When  the  diazo  solution, 
given  below,  has  been  prepared,  pour  into  the  solution 
of  copper  sulphate,  slowly,  while  the  latter  is  heated  on 
a  water-bath,  in  a  hood  with  a  good  draught,  55  grams 
of  potassium  cyanide  dissolved  in  100  cc.  of  water. 
This  converts  the  copper  into  cuprous  cyanide  with 
evolution  of  cyanogen. 

Put  into  a  400  cc.  beaker  21  grams  of  paratoluidine, 
add  150  cc.  of  water,  and  39  grams  (33  cc.)  of  concen- 
trated hydrochloric  acid  (sp.  gr.  1.19).  Add  50  grams 
of  ice,  and  when  the  temperature  has  fallen  nearly  too0, 
add,  in  small  portions,  with  stirring,  a  solution  of  14 
grams  of  sodium  nitrite  in  70  cc.  of  water.  For  a  dis- 
cussion of  the  best  condition  for  Sandmeyer's  reaction 
see  42»  p.  1 16. 

After  five  or  ten  minutes,  having  meanwhile,  com- 
pleted the  preparation  of  the  cuprous  cyanide  solution, 
place  in  the  mouth  of  the  flask  containing  it  a  funnel, 
and  pour  in  the  diazo  solution,  shaking  the  flask  and 
keeping  it  hot  on  a  boiling  water-bath,  taking  care  also 
that  the  solution  does  not  froth  over.  As  soon  as  all  of 
the  solution  has  been  added,  distil  off  the  nitrile  in  a 
rapid  current  of  steam  (see  Fig.  2,  p.  14).  If  the  distillation 
is  sufficiently  rapid,  the  nitrile  will  come  over  with  300 
to  400  cc.  of  water.  Cool  the  distillate  in  ice- water  or  a 
freezing  mixture,  till  the  nitrile  solidifies,  and  separate 
the  latter  by  quick  filtration  on  a  plate,  or  on  a  funnel 
loosely  stoppered  with  cotton- wool.  Care  must  be  taken 
to  transfer  the  nitrile  to  a  dish  or  a  bottle  before  it  melts. 


44  ORGANIC   CHEMISTRY. 

If  thought  better,  the  nitrile  can  be  brought  to  the  sur- 
face by  adding  salt  to  the  water,  or  it  may  be  collected 
with  a  little  ether,  and  separated  with  a  separatory  fun- 
nel. Yield  about  15  grams. 

Tolunitrile  melts  at  28.5°  and  boils  at  218°. 

For  10  grams  of  tolunitrile  take  a  mixture  of  30  cc. 
of  concentrated  sulphuric  acid  with  200  cc.  of  water. 
Boil  in  a  small  round-bottomed  flask  on  an  asbestos  plate 
with  an  upright  condenser  till  crystals  of  toluic  acid  ap- 
pear in  the  latter.  Cool,  dilute,  filter.  Put  the  acid  in 
a  flask,  dissolve  in  a  little  alcohol,  and  add  hot  water  till 
the  solution  becomes  turbid.  Add  2  or  3  grams  of  animal 
charcoal,  boil  a  short  time,  filter  hot,  and  allow  the  acid 
to  crystallize.  Yield  8  to  9  grams  from  10  grams  of  the 
nitrile. 

Toluic  acid  crystallizes  in  white  needles,  which  melt 
at  177°.  It  is  very  easily  soluble  in  alcohol  and  ether, 
and  easily  soluble  in  hot  water.  It  volatilizes  readily 
with  water  vapor.  In  alkaline  solution  it  is  easily  oxi- 
dized to  terephthalic  acid  by  potassium  permanganate. 

10.  Preparation  of  an  Ester  by  Condensation  by  So- 
dium Ethylate.— Acetacetic  ester,  CH8COCH3CO2C2H5. 
(3-Butanonic  ethyl  ester.) 

Literature. — Geuther :  Jsb.  d.  chem.,  1863,  323  ;  1865,  302  ; 
Frankland,  Duppa :  Ann.  Chem.  (Liebig),  135,  220;  138,  204; 
Wislecenus,  Conrad :  Ibid,  186,  214  ;  Michael  :  J.  prakt.  Chem. 
(N.  F.),  37,  473  ;  Nef :  Ann.  Chem.  (Liebig),  266,  62  ;  270,  331 ; 
Freer  :  Am.  Chem.  J.,  13,  310. 

20  grams  sodium. 
200  grams  acetic  ester. 


ACIDS.  45 

60  cc.  glacial  acetic  acid. 

60  cc.  water. 

100  cc.  salt  solution. 

The  acetic  ester  used  for  this  preparation  must  be 
quite  pure,  as  otherwise  its  action  on  sodium  will  be  too 
violent.  If  a  commercial  ester  of  good  quality  is  used, 
it  will  suffice  to  allow  it  to  stand  over  night  with  one- 
fifth  of  its  volume  of  granulated  calcium  chloride,  and 
filter  it  through  a  dry  filter.  If,  however,  the  ester  is 
less  pure  or  has  an  acid  reaction,  it  must  be  shaken 
with  a  strong  solution  of  sodium  carbonate  to  remove 
acetic  acid,  with  a  50  per  cent,  solution  of  calcium  chlo- 
ride to  remove  alcohol,  dried  with  calcium  chloride,  dis- 
tilled, and  dried  again  as  directed  above. 

Place  in  a  750  cc.  flask  20  grams  of  sodium  in  the 
form  of  wire,1  or  cut  in  thin  slices.  Connect  with  a 
large  upright  condenser,  and  pour  through  the  latter  200 
grams  of  acetic  ester.  The  heat  of  the  reaction  should 
cause  the  ester  to  boil,  but  the  reaction  should  not  be 
violent.  When  the  action  appears  to  slacken,  or  if  it 
does  not  commence  after  a  short  time,  place  the  flask  on 
a  water-bath  and  heat  gently  till  the  sodium  has  all  dis- 
solved. This  will  take  one  to  five  hours.  To  the 
slightly  cooled  solution  add,  with  vigorous  shaking,  60 
cc.  of  glacial  acetic  acid  diluted  with  an  equal  volume  of 
water.  The  solution  should  now  react  faintly  acid.  Add 

!•  For  this  and  similar  reactions  the  sodium  is  best  pressed  into  the  form 
of  wire  by  means  of  a  sodium  press.  The  surface  of  the  sodium  must  be  cut 
clean,  and  it  must  not  stand  in  the  air  before  it  is  put  into  the  press.  After 
use,  the  press  should  be  cleaned  with  alcohol  and  dried  immediately. 


40  ORGANIC   CHEMISTRY. 

ioo  cc.  of  a  cold  saturated  solution  of  common  salt, 
shake,  add  enough  water  to  dissolve  any  salt  that  sepa- 
rates, separate  the  upper  layer  containing  the  acetacetic 


To  PUMP 


Fig.  12. 

ester,  by  means  of  a  separatory  funnel,  and  distil  from  a 
500  cc.  distilling  bulb,  best  of  Ladenburg's  form  (Fig.  14) , 
till  the  thermometer  reaches  95°.  This  portion  of  the 
distillate  contains  acetic  ester,  and  may  be  purified 
and  used  again.  Transfer  the  residue  in  the  distilling 
bulb  at  once  to  a  ioo  cc.  distilling  bulb  fitted  with  a 
capillary  tube,  thermometer,  and  a  second  bulb  connected 
to  the  side  tube  to  collect  the  distillate  (Fig.  12) .  Heat  in 
an  oil-bath  or  in  an  air-bath  consisting  of  a  wrought  iron 
crucible,  so  placed  that  the  bulb  does  not  touch  it  at  any 
point.  Distil  under  a  pressure  of  30-40  mm.  till  the 
thermometer  reaches  80°,  or  to  90"  under  a  pressure  of 
ioo  mm.  Change  the  bulb  used  as  a  receiver  and  con- 
tinue the  distillation,  cooling  the  receiver  by  running 


ACIDS. 


47 


water  over  it.  If  the  pressure  remains  constant,  after 
the  boiling-point  of  the  acetacetic  ester  is  reached,  it 
will  all  pass  over  within  an  interval  of  a  few  degrees.  The 
ester  obtained  by  the  first  distillation  should  be  frac- 
tioned  once  or  twice  under  diminished  pressure,  and  the 
ester  finally  obtained  should  boil  within  an  interval 


Fig.  13.  Fig.  14. 

of  2°  to  3°,  if  the  pressure  is  constant.  Yield  45  to  50 
grams. 

The  ester  may  also  be  distilled  under  ordinary  pres- 
sure, but  the  yield  is  much  less. 

The  success  of  this  preparation  depends  very  greatly 
on  rapid  work.  If  sodium  in  the  form  of  wire  is  used, 
the  whole  preparation  should  be  completed  in  three  or 
four  hours.  If  the  preparation  is  interrupted  at  any 
point,  and  especially  if  allowed  to  stand  over  night,  the 
yield  is  greatly  diminished. 

For  the  second  distillation  under  diminished  pressure 


48  ORGANIC   CHEMISTRY. 

a  Claisen  distilling  bulb  (Fig.  13)  can  be  used  with  advan- 
tage. In  all  such  distillations  the  temperature  of  the  oil-  or 
air-bath  should  rise  very  slowly,  and  an  oil-bath  should  not 
be  heated  much  hotter  than  the  boiling-point  of  the 
substance  distilled.  The  capillary  tube  is  to  start  bub- 
bles of  vapor  and  prevent  bumping.  It  is  best  made 
from  a  capillary  tube  5-6  mm.  outside  diameter,  and 
drawn  out  to  fine  thread. 

Many  different  forms  of  apparatus  have  been  devised 
for  distillation  under  diminished  pressure  (Bruhl:  Ber- 
d.  chem.  Ges.,  21,  3339  ;  Lothar Meyer:  Ibid,  20,  1833  ; 
Fuchs  :  Ztschr.  anal.  Chem.,  29,  591  ;  Mabery  :  Am. 
Chem.  J.,  17,  722),  but  for  most  cases  which  arise  in  or- 
dinary practice,  the  simple  apparatus  of  Fig.  12,  if  a 
stream  of  cold  water  is  kept  running  over  the  receiving 
bulb,  answers  every  purpose.  A  good  "  Bunsen"  pump 
which  will  reduce  the  pressure  quickly  to  30  mm.  or  less, 
when  the  water  is  cold,  is,  of  course,  required.  The 
author  has  found  that  of  E.  C.  Chapman,  large  size,  the 
most  satisfactory. 

It  is  very  convenient  to  have  a  manometer  attached 
in  such  a  manner  that  the  pressure  can  always  be  known 
whenever  the  pump  is  used.  That  shown  in  Fig.  15 
has  been  in  use  in  the  author's  laboratory  for  some  years, 
and  has  the  advantage  over  the  usual  forms  that  the 
whole  scale,  from  no  pressure  to  that  of  the  atmosphere,  oc- 
cupies a  space  of  only  about  1 8-20  cm. ,  and  further  that  the 
air  in  the  closed  end  above  the  mercury  acts  as  a  cushion 
and  there  is  no  danger  of  breakage  when  the  pressure  is 
suddenly  released.  If  a  little  fused  caustic  potash  is 


ACIDS. 


49 


placed  in  the  closed  end,  and  the  glass  warmed  enough 
to  cause  it  to  adhere,  the  readings  of  the  manometer 
will,  for  low  pressures,  vary  but  very  little  for  changes 
of  temperature.  The  manometer  is  calibrated  after  it  is 


I 


7*0 
70O 


svo 
•boo 

-300 

200 
/SO 
100 

so 

•  3O 


Fig.  15. 

put  in  position  by  comparison  with  a  manometer  of  the 
usual  form  for  low  pressures,  both  being  connected  with 
the  same  receptacle,  which  is  exhausted  by  the  pump. 
For  higher  pressures  it  is  calibrated  by  connecting  with 
a  small  tube  standing  perpendicularly  in  a  dish  of  mer- 
cury, subtracting  the  height  of  mercury  in  the  tube 
from  the  height  of  the  barometer  for  the  day. 

Acetacetic  ester  is  a  colorless  liquid  with  an  unpleas- 


50  ORGANIC   CHEMISTRY. 

ant  odor.     It  boils  at  181°,  and  has  a  specific  gravity  of 
1.030  at  15°.     Under  diminished  pressure  it  boils: 
Under  12.5  mm.  at    71°. 

"       18.0    "      "     79°. 

"       29.0    "      "     88°. 

11      59-0    "      "     97°- 

"      80.0    "      "   100°. 

It  is  slightly  soluble  in  water  and  is  volatile  with 
water  vapor.  It  gives  a  crystalline  compound  with 
sodium  bisulphite,  which  may  be  used  as  a  means  of 
purification.  It  gives  with  ferric  chloride,  in  aqueous 
solutions,  a  violet  color — characteristic  of  ortho  hydroxy 
derivatives  of  benzoic  acid,  and  of  other  compounds  of 
similar  structure.  It  is  soluble  in  cold  dilute  alkalies 
without  decomposition,  but  on  warming  with  alcoholic 
potash  it  is  decomposed,  chiefly  with  formation  of  two 
molecules  of  acetic  acid  and  alcohol  (acid  decomposi- 
tion). Boiling  it  with  dilute  acids  or  alkalies  decom- 
poses it  mainly  with  the  formation  of  acetone,  carbon 
dioxide,  and  alcohol  (ketonic  decomposition).  For  the 
use  of  acetacetic  ester  in  syntheses,  see  p.  7. 

On  heating  by  itself,  it  decomposes  with  the  formation 
of  dehydracetic  acid,  C8H8O4.  This  can  be  recovered 
from  the  residues  after  distilling  off  the  acetacetic  ester, 
by  boiling  them  with  sodium  carbonate  and  bone-black 
and  crystallizing  the  sodium  salt,  after  filtration.  The 
latter  is  then  decomposed  with  dilute  sulphuric  acid. 
The  acid  crystallizes  in  needles  which  melt  at  109°. 
(Feist:  Ann.  Chem.  (lyiebig),  257,  253.) 

By  condensation  of  acetacetic  ester  with  aldehyde  am- 


ACIDS.  VCA  ,.  51 


monia,  a  pyridine  derivative  is  formed,  with  aniline  a 
chinoline  derivative,  with  phenyl  hydrazine  a  pyrazolone 
compound,  and  with  amidines  pyrimidine  compounds. 

ii.  Condensation  of  Acetacetic  Ester  with  Itself. — 

CH3CO— CH— C03C2H6 
Diacetyl  succinic  ester,  | 

CH3CO— CH— COaC2H5 

Literature. — Rugheimer :  Ber.  d.  chem.  Ges.,  7,  892;  Har- 
row: Ann.  Chem.  (Iviebig),  201,  144;  Nef :  Ibid,  266,88;  Knorr: 
Ber.  d.  chem.  Ges.,  22,  170,  2100;  Paal :  Ibid,  18,  58,  2251. 

150  cc.  dry  ether. 

4  grams  sodium. 

20  grams  acetacetic  ester. 

20  grams  iodine. 

loo  cc.  ether. 

Prepare  some  pure,  dry  ether  as  follows  :!  Fill  a  half 
liter  Brlenmeyer  distilling  bulb  (see  10,  p. 47)  one-fourth 
full  with  granular  calcium  chloride.  Place  in  the  bulb 
an  inverted  test-tube  of  such  size  and  length  as  to  reach 
just  to  the  bottom  of  the  neck  and  nearly  close  it,  when 
resting  on  the  bottom  of  the  bulb.  Fill  the  neck  nearly 
to  the  side  tube  with  granular  calcium  chloride,  and  then 
fill  the  bulb  nearly  to  the  neck  with  ordinary  ether. 
Stopper  the  bulb  and  allow  it  to  stand  over  night.  Then 
distil  on  a  water-bath,  using  a  thermometer,  and  col- 
lecting the  ether  in  a  dry  bottle.  Change  the  receiver 
as  soon  as  the  thermometer  rises  0.2°  above  the  boiling- 
point  of  pure  ether.  The  ether  dried  in  this  way  will 
answer  for  this  preparation.  For  a  perfectly  anhydrous 

1  Method  suggested  by  Dr.  H.  H.  Ballard. 


52  ORGANIC   CHEMISTRY. 

ether  some  sodium  wire  must  be  pressed  into  it,  and  the 
ether  distilled  after  standing  for  a  day. 

Some  chemists  have  recommended  the  drying  of  ether 
with  phosphorus  pentoxide,  but  others  report  that  this 
gives  troublesome  decomposition  products.  It  is  evident 
that  the  method  must  be  used  with  care,  if  at  all. 

Ether  should  be  kept  in  bottles  with  a  smooth  neck, 
and  closed  with  a  tightly  fitting  cork,  not  with  a  glass  or 
rubber  stopper.  The  stock  of  ether  should  be  kept,  as 
far  as  possible,  in  bottles  which  are  filled  full,  as  the  loss 
is  chiefly  due  to  the  expansion  and  contraction  of  the 
air  above  the  ether,  which  always  carries  with  it  some 
of  the  vapor.  The  same  is  true  of  other  volatile  liquids. 

Place  in  a  300  cc.  flask  about  150  cc.  of  dry  ether, 
weigh  carefully,  and  press  into  the  flask  about  four 
grams  of  sodium  wire,  taking  care,  of  course,  that  there 
is  no  appreciable  loss  of  ether  by  evaporation.  Weigh 
again,  connect  with  an  upright  condenser,  and  for  each 
gram  of  sodium  add  five  grams  of  acetacetic  ester. 
Shake  occasionally  till  the  sodium  is  all  dissolved,  which 
will  take  from  one  to  two  hours.  When  an  evolution  of 
hydrogen  is  no  longer  observed,  after  shaking,  add 
in  small  portions  with  shaking,  a  solution  of  about  20 
grams  of  finely  powdered  iodine  in  dry  ether.  Continue 
the  addition  only  so  long  as  the  color  of  the  iodine  disap- 
pears immediately  after  each  addition.  Filter  from  the 
sodium  iodide,  distil  the  ether,  and  crystallize  the  resi- 
due of  diacetsuccinic  ester  from  glacial  acetic  acid. 

Diacetsuccinic  ester  crystallizes  in  needles,  or  in 
onoclinic  plates,  which  melt  at  88°. 


ACIDS.  53 

If  saponified  by  strong  caustic  soda  at  ordinary  tem- 
peratures, the  free  acid  can  be  obtained.  If  saponified 
by  a  3  per  cent,  solution  of  caustic  soda,  in  exactly 
equivalent  amounts,  however,  acetonylacetona,  alcohol, 
and  carbon  dioxide  are  formed. 

12.  Succinylosuccinic  Ester.  — 

CaHB—  O—  CO—  C—  C  (OH)  —  CH2 


a—  C(OH)=C—  CO—  O—  C3H6. 

Literature.  —  Fehling  :  Ann.  Chem.  (L,iebig),  49,  186;  Herr- 
mann: Ibid,  211,  306;  Duisberg:  Ber.  d.  chem.  Ges.,  16,133; 
Wedel:  Ann.  Chem.  (Liebig),  219,94;  Baeyer  :  Ber.  d.  chem. 
Ges.,  19,  432  ;  Mewes  :  Ann.  Chem.  (Ljebig),  245,  74;  Baeyer  u. 
Noyes:  Ber.  d.  chem.  Ges.,  22,  2168;  Pinner:  Ibid,  22,  2623; 
Piutti:  Gaz.  Chim.  Ital.,  20,  167. 

50  grams  succinic  ester. 

I3-5  grams  sodium. 

2  cc.  absolute  alcohol. 

Place  in  a  100  cc.  round-bottomed  flask  50  grams  of  suc- 
cinic ester  (see  29,  p.  89)  and  2  cc.  of  absolute  alcohol. 
Press  into  the  flask  13.5  grams  of  sodium  in  the  form  of 
wire.  (In  such  cases  it  is  desirable  to  know  how  much 
sodium  will  be  left  in  the  press  when  the  piston  is  forced 
to  the  bottom  and  allowance  should  be  made  for  this. 
The  press  must  be  cleaned  with  alcohol  and  dried  im- 
mediately after  use.)  During  the  addition  of  the 
sodium  have  a  dish  of  cold  water  at  hand,  and  cool  the 
flask  by  immersion  in  this,  if  the  reaction  becomes  vio- 
lent. The  flask  should  always  be  allowed  to  grow 
warm,  but  should  not  become  so  hot  as  to  melt  the 


54  ORGANIC   CHEMISTRY. 

sodium.  When  the  sodium  has  all  been  added,  and  the 
reaction  has  progressed  far  enough  so  that  the  mixture 
no  longer  tends  to  grow  hot,  connect  the-  flask  with  an 
upright  condenser  and  heat  on  a  water-bath  for  two 
hours.  Stopper  the  flask  and  allow  it  to  cool.  The 
mixture  can  be  left  at  this  point  over  night  without 
harm,  perhaps  with  advantage.  The  yield  can  be  in- 
creased by  longer  heating  or  by  longer  standing,  but  the 
time  taken  is  usually  worth  more  than  the  material 
saved.  The  contents  of  the  flask  should,  at  the  end  of 
the  time,  be  converted  into  a  dry  solid  mass. 

Put  into  a  500  cc.  beaker  200  cc.  of  water  and  150  cc.  of 
dilute  sulphuric  acid  (25  percent.,  sp.  gr.  1.18).  Set 
the  beaker  in  a  large  dish  of  cold  water,  and  conduct  to 
the  surface  of  the  acid  a  slow  current  of  carbon  dioxide, 
which  will  prevent  the  particles  of  unchanged  sodium 
from  taking  fire  as  they  dissolve  in  the  acid.  Add  the 
material  from  the  flask  to  the  acid  in  small  portions  with 
vigorous  stirring.  It  is  frequently  necessary  to  break 
the  flask  to  get  the  sodium  salt,  but  the  latter  should  not 
be  exposed  to  the  air  long  before  it  is  thrown  into  the 
acid. 

The  crude  succinylosuccinic  ester  which  separates  is 
filtered  off  on  a  plate,  and  washed  with  cold  water.  The 
crude  ester,  after  sucking  as  dry  as  possible,  is  then 
crystallized  from  hot  alcohol.  For  this  purpose  put  in  a 
500  cc.  flask  about  300  cc.  of  alcohol  and  add  the  ester  only 
in  such  quantity  that  it  will  dissolve  quite  readily  on 
boiling  the  alcohol  on  a  water-bath.  Filter  hot  and 
very  quickly  on  a  plate,  transfer  the  filtrate  to  a  clean 


ACIDS.  55 

flask  and  cool  rapidly  under  the  tap  till  the  ester  has 
crystallized.  Filter  on  another  plate  with  a  clean  filter. 
Transfer  the  filtrate  to  the  first  flask,  add  more  of  the 
ester,  boil,  filter,  crystallize,  and  collect  the  crystals  on 
top  of  the  first  lot.  Repeat  till  all  of  the  ester  has  been 
crystallized,  then  wash  the  crystals  once  with  pure  alco. 
hoi  and  repeatedly  with  dilute  alcohol. 

Succinylosuccinic  ester  forms  yellowish  or  greenish 
crystals  which  melt  at  127°.  It  is  almost  insoluble  in 
cold  water,  slightly  soluble  in  hot  water,  and  difficultly 
soluble  in  cold  alcohol.  The  pure  alcoholic  solution  has 
a  beautiful  blue  fluorescence,  and  is  colored  onion-red  by 
ferric  chloride.  The  ester  dissolves  in  dilute  caustic 
soda,  and  is  saponified  with  formation  of  the  products  of 
both  acid  and  ketonic  decomposition  by  allowing  the 
solution  to  stand  (Herrmann  :  Ann.  Chem.  (L,iebig),  211, 
322).  A  clean  ketonic  decomposition  with  the  forma- 
tion of  diketohexamethylene  (cyclohexandion  1.4)  can 
be  obtained  by  boiling  with  dilute  sulphuric  acid. 
(Baeyer:  Ann.  Chem.  (Liebig),  278,  91.) 

By  suspending  in  carbon  disulphide  and  treating  with 
the  calculated  amount  of  bromine,  it  is  converted  quan- 
titatively into  dioxyterephthalic  ester. 

13.  Synthesis  of  an  Acid  by  Condensation  of  Acet- 
acetic  Ester  with  a  Halogen  Compound. — Hydrocin- 
namic  acid,  C6H6CH2CH2CO2H  (Phen-3-propanoic 
acid).1 

1  This  acid  is  called,  in  the  Third  Edition  of  Beilstein,  phenathylsaure,  but 
that  name  does  not  agree  with  the  principles  of  nomenclature  proposed  by 
the  Geneva  Congress,  and  Beilstein  uses  the  same  name  elsewhere  for  a-tol- 
uic  acid,  C6H5CH2COaH. 


56  ORGANIC   CHEMISTRY. 

Literature.— Alexejew,  Erlenmeyer :  Ann.  Chem.  CLiebig), 
I2I>  375  ;  i37»  327 ;  Gabriel,  Zimmermann  :  Ber.  d.  chem.  Ges., 
13,  1680 ;  Fittig,  Kiesow  :  Ann.  Chem.  (Liebig),  156,  249 ;  Sese- 
mann:  Ber.  d.  chem.  Ges.,  6,  1086;  10,  758;  Conrad,  Hodgkin- 
son  :  Ann.  Chem.  (Liebig),  193,  300;  Conrad:  Ibid,  204,  136; 
Conrad,  Bischoff :  Ibid,  204,  180 ;  Fittig,  Christ :  Ibid,  268,  122. 
For  benzyl  acetone,  Ehrlich  :  Ibid,  187,  n  ;  Jackson:  Ber.  d. 
chem.  Ges.,  14,  890;  Harries,  Eschenbach  :  Ibid,  29,  383. 

2.3  grams  sodium. 
35  cc.  absolute  alcohol. 
13  grams  acetacetic  ester. 
12.6  grams  benzyl  chloride. 

15  grams  (about)  benzyl  acetacetic  ester. 

30  cc.  alcohol. 

10  grams  sodium  hydroxide. 

30  cc.  water. 

40  cc.  hydrochloric  acid  (sp.  gr.  i.u). 

Put  2.3  grams  (i  mol.)  of  sodium  in  a  100  cc.  flask. 
Add  35  cc.  of  absolute  alcohol,  connect  with  an  up- 
right condenser,  and  heat  on  a  water-bath  till  the  sodium 
is  dissolved.  Cool,  add  13  grams  (i  mol.)  of  acetacetic 
ester,  which,  on  shaking,  will  cause  the  sodium  ethylate, 
which  has  separated,  to  dissolve.  Add  12.6  grams  (i 
mol.)  of  benzyl  chloride,  and  heat  on  the  water-bath  with 
an  upright  condenser  for  two  hours.  The  solution  should 
now  react  neutral  when  a  piece  of  dry  reddened  litmus 
paper  is  dipped  in  it  and  afterwards  moistened.  Cool, 
filter  on  a  dry  filter  with  the  pump,  and  wash  twice  with 
a  little  alcohol.  Distil  the  solution  under  ordinary  pres- 
sure till  the  thermometer  reaches  110°,  and  then  under 


ACIDS.  57 

diminished  pressure,  using  an  oil- or  air-bath.  The  Clai- 
sen distilling  bulb  may  be  used  with  advantage  (see  io,p. 
47).  The  portion  boiling  at  160°— 170°  under  a  pressure 
of  12  mm.,  or  i8o°-i9O°  under  a  pressure  of  100  mm., 
will  be  nearly  pure  benzyl  acetacetic  ester, 

XCOCH3 
C6H-CH,-CH( 

XC02C,H6 

A  small  portion,  which  boils  at  70°  higher,  consists  of 
dibenzyl  acetacetic  ester;  12-15  grams  of  the  monoben- 
zyl  acetacetic  ester  should  be  obtained. 

Put  the  benzyl  acetacetic  ester  in  a  200  cc.  flask,  add 
30  cc.  of  alcohol,  and  10  grams  of  sodium  hydroxide  dis- 
solved in  30  cc.  of  water.  Boil  with  an  upright  con- 
denser for  an  hour.  Cool,  dilute  with  about  50  cc.  of 
water,  and  extract  twice  with  10-20  cc.  of  ether.  Distil 
off  the  ether,  dry  the  ketone  which  remains  in  vacuo 
over  sulphuric  acid,  and  distil ;  or  the  ethereal  solution 
may  be  dried  with  ignited  potassium  carbonate  before 
the  ether  is  distilled  away. 

Evaporate  the  alkaline  solution  to  about  20  cc.  and 
add  40  cc.  of  hydrochloric  acid  (sp.  gr.  i.n).  Thehy- 
drocinnamic  acid  usually  separates  as  an  oil,  at  first,  but 
will  solidify  on  standing  in  a  cool  place  for  some  time. 
Filter,  and  recrystallize  from  hot  water,  reserving  a  very 
small  crystal  to  cause  the  solidification  of  the  acid,  in 
case  it  separates  again  as  an  oil. 

The  yield  of  the  ketone  and  of  the  acid  is  about  3 
grams  each,  but  better  yields  may  be  obtained  by  work- 
ing with  larger  quantities. 


58  ORGANIC    CHEMISTRY. 

Benzyl  acetone  (i3-butylonphen)  C6HBCH2CH2COCH8 
is  a  liquid  which  boils  at  2^-2^6°,  and  has  a  specific 

Q 

gravity  of  0.989  at  -^5. 

Hydrocinnamic  acid  crystallizes  in  long  colorless  nee- 
dles, which  melt  at  49°.  It  boils  at  280°.  It  is  easily 
soluble  in  boiling  water,  and  in  alcohol  and  ether.  It  is 
volatile  in  water  vapor.  It  dissolves  in  168  parts  of 
water  at  20°. 

14.  Condensation  of  an  Aldehyde  with  the  Sodium 
Salt  of  an  Acid.  Perkin's  Synthesis.  — Cinnamic  acid, 
C6HB— CH=CHCO2H. 

Literature.— Perkin  :  Jsb.  d.  chem.,  1877,  789  ;  J.  Chem.  Soc., 
31,  388  ;  Tiemann,  Herzfeld  :  Ber.  d.  chem.  Ges.,  10,  68  ;  Edele- 
ano,  Budistheano  :  Bull.  Soc.  China.  [3],  3,  191;  Michael  :  Am. 
Chem.  J.,  5,  205.  Also  see  next  preparation. 

20  grams  benzaldehyde. 

30  grams  acetic  anhydride. 

10  grams  sodium  acetate. 

In  a  100  cc.  flask  place  10  grams  of  recently  fused 
and  powdered,  dry,  sodium  acetate,  30  grams  acetic 
anhydride,  and  30  grams  benzaldehyde,  both  recently 
distilled.  Connect  with  an  upright  air  condenser  tube, 
i  cm.  in  diameter  and  60-80  cm.  long.  Heat  in  a  small 
paraffin  bath  to  the  boiling-point  of  the  mixture,  about 
1 80°,  for  eight  hours.  Pour  the  contents  of  the  flask 
while  hot  into  a  500  cc.  flask  or  distilling  bulb.  Rinse 
out  with  hot  water  and  then  distil  with  water  vapor  as 
long  as  benzaldehyde  comes  over.  Add  more  water,  if 
necessary,  to  dissolve  the  cinnamic  acid,  and  a  little 


ACIDS.  59 

bone-black.  Boil  and  filter  hot  on  a  plain  or  plaited 
filter,  previously  moistened.  The  cinnamic  acid  will 
crystallize  from  the  filtrate  on  cooling.  If  it  does  not 
have  the  proper  melting-point,  recrystallize  from  hot 
water. 

Cinnamic  acid  crystallizes  from  water  in  colorless 
needles  or  leaflets,  which  melt  at  133°.  It  dissolves  in 
3500  parts  of  water  at  17°,  much  more  easily  in  hot 
water.  It  combines  with  bromine  to  form  a  dibromide, 
C6H5CHBr.CHBrCO,H,  which  on  treatment  with  alco- 
holic potash  gives  phenyl  propiolic  acid,  C6H5C^^C  — 
CO2H.  Ordinary  cinnamic  acid  appears  to  be  the  cis- 

C6H5— CH 
trans  modification,  ||  .  Two  other  forms, 

H  — C— CO2H 

one  called  isocinnamic  acid,  which  melts  at  57°,  and  one 
called  allocinnamic  acid,  which  melts  at  68°,  are  known, 
but  the  causes  of  the  isomerism  are  not  fully  understood. 
L,iebermann  :  Ber.  d.  chem.  Ges.,  23,  141,  2511;  24, 
1102;  25,  950;  26,  1572;  27,  2038;  Fock:  Ibid,  23, 
147,  2511  ;  24,  1105  ;  27,  2048  ;  Ostwald  :  Ibid,  23,  516  ; 
24,  1106  j  Stohmann  :  Ztschr.  phys.  Chem.,  10,  418. 

15.  Condensation  of  an  Aldehyde  with  a  Ketone  and 
Oxidation  of  the  Acetyl  Group  with  Sodium  Hypochlo- 

rite.— Cinnamic  acid,  C8HBCH=CHCO2H. 

Literature. — See  last  preparation,  also  Enjjler,  Leist :  Ber.  d. 
chem.  Ges.,  6,  254,  257;  Claisen,  ClaparMe :  Ibid,  14,  2461; 
Claisen,  Ponder:  Ann.  Chem.  (L,iebig),  223,  139;  J.  G.  Schmidt: 
Ber.  d.  chem.  Ges.,  14,  1460  ;  Meister,  I/ucius  and  Briining,  D.  R. 
P.,  21162,  Ibid,  16,  449. 


60  ORGANIC   CHEMISTRY. 

10  grams  benzaldehyde. 

25  cc.  acetone. 

10  cc.  caustic  soda  (10  per  cent.). 

900  cc.  water. 

In  a  one  liter  flask  place  900  cc.  of  water,  10  grams  of 
benzaldehyde,  25  cc.  acetone  and  10  cc.  of  caustic  soda, 
free  from  carbonate.  Mix  thoroughly  by  shaking  and 
allow  to  stand  for  four  days,  shaking  occasionally.  The 
aldehyde  and  acetone  condense  with  the  formation  of 
benzalacetone,  C6H6  — CH=CHCOCH9,  and  dibenzal- 
acetone,  C6H5  —  CH~CH  —  CO  —  CH=CH  —  C6HB. 
Add  200  grams  of  salt  (see  8,  p.  38)  and  filter  off  and  wash 
the  dibenzal-acetone  if  it  is  solid,  or  extract  twice  with 
a  small  amount  of  ether,  if  it  is  liquid.  Distil  off  the 
ether  and  fractionate  the  benzalacetone  from  a  small 
distilling  bulb  (see  Fig.  12,)  under  diminished  pressure. 
The  benzalacetone  distils  at  I5i°-i53°  under  25  mm. 
pressure,  at  26o°-262°  under  760  mm.,  and  melts  at  42°. 

2.5  grams  benzalacetone. 
12  grams  chloride  of  lime. 
15  grams  sodium  carbonate. 
125  cc.  water. 

To  12  grams  of  chloride  of  lime  (containing  31  per 
cent,  of  available  chlorine)  add  50  cc.  of  water  and  75 
cc.  of  a  solution  of  sodium  carbonate  (5  cc.  =  i  gram 
Na,CO8).  Filter  with  the  pump  and  wash  once.  To 
the  filtrate  add  2.5  grams  of  benzalacetone,  warm  to  8o°- 
90°  and  shake  vigorously.  Continue  to  warm  and  shake 
till  the  odor  of  chloroform  is  no  longer  apparent.  The 


ACIDS.  6 1 

benzalacetone  should  now  have  passed  into  solution. 
Cool,  filter,  precipitate  the  cinnamic  acid  with  sul- 
phuric acid  and  recrystallize  from  hot  water.  The  oxi- 
dation is  exactly  analogous  to  that  by  which  chloroform 
is  prepared  commercially  from  acetone.  For  the  prop- 
erties of  cinnamic  acid  see  above. 

16.  Preparation  of  Acids  by  Decomposition  of  Bibasic 
Acids. — Formic  acid,  H.CO2H.  (Methanoic  acid.) 

Literature. — Berthelot :  Ann.  Chim.  Phys.  [3],  46,  477; 
Ann.  Chem.  (Iviebig),  98,  139;  Seekamp  :  Ibid,  122, 113;  korin  : 
Ann.  Chim.  Phys.  [4],  29,  367  ;  Romburgh  :  Compt.  Rend.,  93, 
847;  Roscoe  :  Ann.  Chem.  (Liebig),  125,  320;  Maquenne :  Bull. 
Soc.  Chim.  [2],  50,  662  ;  I/iebig :  Ann.  Chem.  (Iviebig),  171  69. 

50  grams  glycerine. 

50  grams  oxalic  acid. 

Place  in  a  150  cc.  distilling  bulb  50  grams  of  glycerine, 
and  50  grams  of  crystallized  oxalic  acid.  Insert  a  ther- 
mometer, immersed  in  the  liquid.  Connect  with  a  con- 
denser, and  heat  with  a  low  flame  till  the  thermometer 
rises  slowly  to  105°.  Allow  to  cool  to  about  50°,  add  50 
grams  more  of  oxalic  acid  and  distil  again,  always  over 
a  low  flame  and  slowly  to  a  temperature  of  115°.  Repeat 
almost  indefinitely,  distilling  to  a  temperature  of  115°- 
125°.  The  acid  coming  over  in  the  later  distillations 
will  be  stronger  than  that  of  the  first.  The  residue  may 
be  used  for  the  preparation  of  allyl  alcohol  (see  68.) 

Pure  formic  acid  cannot  be  obtained  from  the  dilute 
acid  by  distillation,  the  tendency  being  for  a  dilute  acid 
to  become  more  concentrated,  or  a  concentrated  acid 
weaker  by  distillation,  till  an  acid  boiling  at  107°  and  of 


62  ORGANIC   CHEMISTRY. 

77  per  cent,  finally  passes  over.  Weaker  acids  may  be 
concentrated  to  this  strength  by  distillation.  A  nearly 
anhydrous  acid  can  then  be  obtained  by  dissolving  an- 
hydrous oxalic  acid  in  this  acid  with  the  aid  of  heat,  in 
such  amount  that  on  crystallizing  with  two  molecules  of 
water  it  will  somewhat  more  than  combine  with  all  of  the 
water  present.  After  the  oxalic  acid  has  crystallized, 
the  formic  acid  is  poured  off  and  distilled. 

An  anhydrous  acid  may  also  be  obtained  by  the  de- 
composition of  the  lead  salt  with  hydrogen  sulphide. 

Formic  acid  melts  at  8.3°,  boils  at  101°,  and  has  a  spe- 
cific gravity  of  1.2256  at  15°.  The  lead  salt,  which  is 
easily  prepared  by  dissolving  lead  carbonate  in  the  hot 
dilute  acid,  is  the  most  characteristic.  It  dissolves  in 
5^  parts  of  hot  water,  and  in  63  parts  of  water  at  16°. 
The  copper  salt  also  crystallizes  well. 

When  heated  with  concentrated  sulphuric  acid,  formic 
acid  decomposes  into  water  and  carbon  monoxide.  On 
warming,  it  reduces  solutions  of  silver  salts  with  the  sep- 
aration of  metallic  silver.  On  warming  with  mercuric 
chloride  calomel  separates.  On  heating  the  sodium  salt 
with  caustic  soda,  hydrogen  is  liberated. 

The  specific  gravity  of  the  dilute  acid  is  as  follows  : 

Per  cent.  CH3Oa.  Specific  gravity  at  15°. 

10  .025 

30  .080 

50  .124 

70  .l6l 

loo  .223 


ACIDS.  63 

17.  Preparation  of  Acids  from  Natural  Products. — 

Stearic  acid,  C17H33CO2H. 

Literature. — Pebal :  Ann.  Chem.  (Liebig),  91,  138;  Heintz  : 
Ann.  Chem.  (I/iebig),  92,  295;  Carnelly,  Williams:  Ber.  d. 
chem.  Ges.,  12,  1360 ;  J.  Chem.  Soc.,  35.563;  Krafft:  Ber.  d. 
chem.  Ges.,  15,  1724;  16,  1722;  Saunders  :  Jsb.  d.  Chem.,  1880, 
831  ;  David  :  Ztschr.  anal.  Chem.,  18,  622  ;  Krafft :  Ber.  d.  chem. 
Ges.,  22,  819  ;  Hehner  and  Mitchell  :  J.  Am.  Chem.  Soc.,  19,  32. 

ioo  cc.  alcohol. 

100  grams  tallow. 

35  grams  potassium  hydroxide. 

35  cc.  water. 

90  cc.  hydrochloric  acid  (sp.  gr.  i.i). 

Magnesium  acetate. 

Melt  ioo  grams  of  tallow  and  pour  it  into  a  500  cc. 
flask,  add  ioo  cc.  of  alcohol  and  warm  on  a  water-bath. 
Add  in  small  portions  35  grams  of  caustic  potash  dis- 
solved in  35  cc.  of  water.  After  all  has  been  added, 
dilute  with  200  cc.  of  cold  water.  Add  90  cc.  of  hydro- 
chloric acid  (4  cc.  =  i  gram),  and  warm  till  the  fatty 
acids  melt  and  collect  on  top.  Cool  and  separate  the 
acids  from  the  solution.  Dissolve  the  acids  in  500  cc. 
of  warm  alcohol,  cool  somewhat,  and  add  enough  of  a 
solution  of  magnesium  acetate1  to  precipitate  20  grams 
of  stearic  acid.  Stir  for  five  minutes,  filter  on  a  plate, 
and  wash  once  with  strong  alcohol.  To  the  filtrate  add 
the  same  amount  of  the  acetate,  filter  on  a  new  filter, 
and  repeat  as  often  as  a  precipitate  is  obtained.  From 

1  Prepare  the  solution  by  dissolving  16.8  grams  of  magnesium  carbonate 
or  8  grams  of  freshly  ignited  magnesium  oxide  in  85  cc.  of  acetic  acid  (30  per 
cent.),  filtering,  and  washing  to  a  volume  of  ioo  cc.  One  cc.  of  the  solution 
will  precipitate  1.136  grams  stearic  acid. 


64  ORGANIC   CHKMISTRY. 

the  last  filtrate  an  impure  oleic  acid  can  be  precipitated 
by  water. 

Decompose  each  of  the  magnesium  precipitates  sepa- 
rately by  warming  and  stirring  with  dilute  hydrochloric 
acid  till  the  fatty  acid  separates  and  melts  to  a  clear 
liquid,  and  then  allow  each  to  cool  and  solidify.  Crys- 
tallize each  portion  of  the  acids  obtained  from  15-20 
times  its  weight  of  strong  alcohol.  Determine  the  melt- 
ing of  each  set  of  crystals  obtained,  unite  portions  hav- 
ing nearly  the  same  melting-point  and  crystallize  again, 
and  repeat  till  a  considerable  quantity  of  pure  stearic 
acid  is  obtained.  It  will  usually  be  found  best  to  crys- 
tallize rather  slowly  by  spontaneous  cooling,  and  not  to 
allow  the  temperature  to  fall  too  low. 

The  impure  oleic  acid  referred  to  above  may,  if  de- 
sired, be  converted  into  the  lead  salt  by  digesting  with 
litharge  on  the  water-bath,  and  the  lead  oleate  separated 
from  the  lead  salts  of  other  acids  by  solution  in  ether,  or 
in  alcohol  (of  sp.  gr.  0.82)  at  65°.  The  oleic  acid  is  set 
free  by  digesting  the  salt  with  hydrochloric  acid,  the 
acid  converted  into  the  barium  salt,  and  the  latter  crys- 
tallized from  alcohol.  (Gottlieb:  Ann.  Chem.  (Liebig), 
57,  38.) 

Distillation  under  diminished  pressure  may  also  be 
used  with  advantage  in  purifying  the  fatty  acids.     The 
boiling-points  and  melting-points  are  as  follows  : 
BOILING-POINTS. 

Palmitic.  Stearic.  Oleic. 

At    15  mm.  215°  232°  232°. 5 

11    100     "  27i°.5  291°  286° 

"760     "  339°-356°  359°-383° 


ACIDS.  65 

MBI/TING-POINTS. 
Palmitic.  Stearic.  Oleic. 

62°  69. 2°  or  7i°-7i.5°      14° 

Stearic  acid  crystallizes  from  alcohol  in  leaflets.     It  is 

soluble  in  40  parts  of  cold  absolute  alcohol,  in  its  own 

weight  of  alcohol  at  50°. 

Palmitic  acid  dissolves  in   10  parts  of  cold  alcohol. 

loo  cc.   of  alcohol  of  sp.  gr.   0.8183  will  dissolve  at  o° 

about  0.15  gram  of  stearic  acid  and  about  1.2  gram  of 

palmitic  acid.     (Hehner  and  Mitchell.) 
18.  Uric  Acid. 

NH— CO  N  =  COH 

/I  II 

CO  C— NH.  or      COHC  — NH 

\         II         )co,         ii      ii      \COH 

NH— C— NH  /  N  —  C— N  s  u 

Literature. — Liebig  and  Wohler:  Ann.  Chem.  (Liebig),  26, 
245  ;  Wohler :  70,  229 ;  88,  100 ;  Arppe  :  Ibid,  87,  237 ;  Goes- 
mann :  Ann.  Chem.  (I/iebig),  99,  374;  Gibbs  :  Ztschr.  Chem., 
1869,  729 ;  Am.  J.  Sci.,  48,  215  (1869)  ;  Ann.  Chem.  (I^iebig), 
Supl.,  Bd.  7,  324  ;  Horbaczewski  :  Ber.  d.  chem.  Ges.,  15,  2678  ; 
Behrend  u.  Roosen  :  Ber.  d.  chem.  Ges.,  21,  999 ;  Ann.  Chem. 
(L,iebig),  251,  235  ;  Formanek  :  Ber.  d.  chem.  Ges.,  24,  3419  ; 
Ann.  Supl.,  Bd.  2,  313  ;  Fresenius  :  Ztschr.  anal.  Chem.,  2,  456  ; 
Salkowski :  Ibid,  16,  373  ;  B.  Fischer:  Ber.  d.  chem.  Ges.,  17, 

1785 ;  30, 549. 

i  liter  urine. 

25  cc.  concentrated  hydrochloric  acid. 

Add  to  one  liter  of  urine  25  cc.  of  concentrated  hydro- 
chloric acid  and  allow  to  stand  in  a  cool  place  for  two 
days.  Decant  the  liquid  from  the  crystals  of  uric  acid 
and  wash  them  by  decantation.  Transfer  to  a  test-tube, 


66  ORGANIC   CHEMISTRY. 

dissolve  in  the  smallest  possible  amount  of  5  per  cent, 
sodium  hydroxide,  add  a  drop  of  a  solution  of  potassium 
pyrochromate  and  boil ,  then  add  a  little  bone-black ,  shake , 
and  filter.  Precipitate  the  uric  acid  with  hydrochloric 
acid,  allow  to  separate  completely,  filter,  and  wash.  In 
working  with  larger  amounts  of  uric  acid  the  amount  of 
the  pyrochromate  should  be  five  per  cent,  of  that  of  the 
uric  acid,  and  after  the  second  precipitation  the  uric 
acid,  which  is  slightly  yellow,  should  be  warmed  several 
times  with  strong  hydrochloric  acid,  till  it  is  perfectly 
white.  (Gibbs:  Loc.  tit.) 

The  yield  from  one  liter  of  urine  will  usually  be  one- 
half  a  gram  or  less. 

Uric  acid  forms  a  white  crystalline  powder,  which  is 
almost  insoluble  in  water,  alcohol,  and  ether.  It  dis- 
solves in  alkalies  with  the  formation  of  salts  in  which 
two  atoms  of  hydrogen  are  replaced  by  the  metal.  Car- 
bon dioxide  precipitates  from  such  solutions  difficultly 
soluble  acid  salts,  a  property  used  in  the  preparation  of 
the  acid  from  guano.  It  is  precipitated  from  its  solu- 
tions by  an  ammoniacal  solution  of  silver  nitrate.  If  a 
little  uric  acid  is  moistened  with  nitric  acid,  and  the 
solution  evaporated  on  the  water-bath,  the  residue  dis- 
solves in  ammonia  to  an  onion-red  solution,  which  be- 
comes violet  on  adding  sodium  hydroxide  ("murexid 
reaction"). 

Nitric  acid  oxidizes  uric  acid  to  alloxan, 

XNH— CO. 

C0(  )C(OH)8  +  3HaO,  « 

XNH— COX 


ACIDS.  67 

and  the  latter  is  decomposed  by  alkalies  into  urea  and 
mesoxalic  acid, 


XCO2H 

The  structural  formulae  given  above  are  based,  in 
part,  on  these  reactions. 

i9.  Preparation  of  Levulinic  Acid  by  the  Action  of  a 
Dilute  Acid  on  a  Carbohydrate, 

CH3COCH,CH8C02H. 

Literature  —  Noeldecke  :  Ann.  Chem.  (Liebig),  149,  224,  228; 
Bente  :  Ber.  d.  chem.  Ges.,  8,  416;  Tollens  and  Kehrer:  Ann. 
Chem.  (Liebig),  175,  181  ;  206,  207  ;  Conrad  :  Ber.d.  chem.  Ges., 
ii,  2178;  Fittig  and  Wolff:  Ann.  Chem.  (Liebig),  208,105; 
Kent  and  Tollens  :  Ibid,  227,  229  ;  Conrad  and  Gutzeit  :  Ber.  d. 
chem.  Ges.,  18,442;  19,  2572;  Neugebauer  :  Ann.  Chem.  (Lie- 
big),  227,  99  ;  Rischbeth  :  Ber.  d.  chem.  Ges.,  20,  1773  ;  Weh- 
mer  and  Tollens  :  Ann.  Chem.  (Liebig),  243,  314;  Seissl:  Ibid, 
249>  275  ;  Fittig  ;  Ber.  d.  chem.  Ges.,  29,  2583. 

ioo  grams  sugar. 

400  cc.  water. 

ioo  cc.  concentrated  hydrochloric  acid. 

Put  in  a  750  cc.  flask  ioo  grams  of  cane  sugar,  400  cc. 
of  water,  and  ioo  cc.  of  concentrated  hydrochloric  acid. 
Close  the  flask  with  a  tube  containing  water  as  in  the 
preparation  of  camphoric  acid  (see  3»  p.  21).  Heat  on  a 
water-bath  for  20  hours.  Filter  on  a  plate,  boil  the  resi- 
due of  humus  with  ioo  cc.  of  water  and  filter.  To  the 
combined  filtrates  add  a  solution  of  35  grams  of  sodium 
hydroxide,  and  evaporate  to  about  ioo  cc.  Filter  again, 
ii  necessary,  and  extract  four  or  five  times  with  50—75  cc. 
of  ether,  distilling  the  ethereal  extract  and  using  the 


68  ORGANIC   CHEMISTRY. 

same  ether  each  time.  For  such  cases  it  is  convenient 
to  put  a  separatory  funnel  through  the  stopper  of  the 
distilling  bulb  so  that  the  ether  may  be  introduced  con- 
tinuously and  without  removing  the  bulb  from  the 
water-bath.  A  funnel  should  be  placed  in  the  mouth  of 
the  separatory  funnel  to  facilitate  the  pouring  of  the 
ether,  and  care  must  always  be  taken  to  avoid  ignition 
of  the  latter. 

After  distilling  off  the  ether,  transfer  the  residue  to  a 
smaller  distilling  bulb,  and  distil  under  diminished  pres- 
sure, raising  the  temperature  of  the  oil-  or  air-bath 
slowly.  Collect  the  portion  boiling  at  i4O°-i6o°  under 
15  mm.,  or  at  i6o°-i8o°  under  80-100  mm.  Put  this 
portion  in  a  wide-mouthed,  tightly-stoppered  bottle  and 
allow  it  to  stand  at  o°  for  some  time,  till  it  has  solidified 
as  far  as  possible.  Pour  off  the  liquid  part,  warm  the 
residue  gently  till  it  melts,  and  allow  it  to  crystallize 
slowly  at  ordinary  temperatures.  After  draining  off  the 
liquid  part  the  solid  acid  will  be  nearly  pure.  Yield  10- 
15  grams. 

The  reactions  which  take  place  are,  first,  the  inver- 
sion of  the  cane  sugar  to  levulose  and  glucose,  and  then 
the  decomposition  of  these  into  levulinic  and  formic 
acids  and  water. 

CH2OH 
CHOH 

CHOH   =  CH3COCH2CH2C02H  +  HCO2H  +  H2O. 

CHOH 
CHO 


ACIDS.  69 

Levulinic  acid  melts  at  33°,  and  boils  with  slight  de- 
composition at  245°-246°  under  760  mm.  pressure,  or  at 
1 48°- 1 49°  under  15  mm.  If  heated  for  some  time  at  its 
boiling-point,  it  is  converted  into  a  mixture  of  a-  and 
yff-angelica  lactones, 

CH3— C  =  CH— CHaCO  and  CH3  =  C— CH2CHa— CO. 

O '  O » 

It  gives  with  phenylhydrazine  a  crystalline  hydrazone, 
and  is  reduced  to  ^-hydroxyvaleric  acid  by  sodium 
amalgam.  On  acidifying  a  solution  of  the  sodium  salt 
of  this  acid,  valerolactone  separates. 


II. 


Derivatives  of  Acids* 

The  derivatives  of  organic  acids  are  of  two  classes  : 
those  derivatives  in  which  the  carboxyl  (CO3H)  group 
is  affected,  and  those  in  which  the  rest  of  the  acid  is 
changed.  To  the  former  class  belong  salts,  chlorides, 
anhydrides,  amides,  and  esters  ;  to  the  latter,  halogen 
derivatives,  nitro  derivatives,  amino-acids,  hydroxy- 
acids,  and,  indeed,  nearly  or  quite  all  classes  of  deriva- 
tives which  may  be  formed  from  hydrocarbons. 

The  chlorides  of  acids  are  prepared  by  treatment  of  the 
acid,  or  one  of  its  salts,  with  phosphorus  trichloride, 
phosphorus  pentachloride  or  phosphorus  oxy chloride. 
The  trichloride  is  usually  used  for  the  lower  members  of 
the  fatty  acid  series,  and  for  cases  where  the  boiling- 
point  of  the  chloride  is  near  that  of  phosphorus  oxy- 
chloride. 

O  O 

3RC— OH  +  2PC13  =  3R— C— Cl  +  3HC1  +  P2O3. 

For  other  cases,  and  especially  when  acids  react  with 
difficulty,  phosphorus  pentachloride  is  used. 

O  O 

R— C— OH  +  PC16  =  R— C— Cl  +  POC13  +  HC1. 

Phosphorus  oxy  chloride  is  rarely  used  except  with  the 
salts  of  acids. 


DERIVATIVES  OF  ACIDS.  71 

o  o 

/f  ^b 

2R— C— ONa+  POC13  =  2R—C— Cl  +  NaPOs  +  NaCl. 
The  anhydrides  of  monobasic  acids  are  usually  pre- 
pared by  the  action  of  the  chloride  of  the  acid  on  its 
sodium  salt. 

00 

S        % 
R— COC1  +  RCO.ONa  =  R— C  —  O  —  C— R  +  NaCl. 

In  some  cases  an  excess  of  the  alkaline  salt  is  treated 
with  phosphorus  oxy chloride. 

4R— CO.ONa+ POC13  =   NaPO8  +  3NaCl  + 
2R— CO— O— CO— R. 

Bibasic  acids  in  which  the  two  carboxyl  groups  are 
separated  by  two  carbon  atoms,  either  in  the  aliphatic 
or  aromatic  series  (succinic  and  phthalic  acids  and  their 
derivatives),  readily  form  inner  anhydrides,  in  most 
cases  by  the  action  of  heat  alone  and  at  temperatures 
below  210°.  (Auwers:  Ann.  Chem.  (L,iebig),  285,  223.) 
The  formation  of  such  anhydrides  can  be  effected  at 
lower  temperatures,  and  in  most  cases  quantitatively  by 
the  use  of  acetyl  chloride,  acetic  anhydride,  or  phos- 
phorus oxychloride. 

2R<C02H  +  POC1°  =  2R<CO>0  +  3HC1  + 
HPO3. 

Glutaric  acid  and  its  derivatives  with  open  chains  and, 
apparently,  the  "cis"  forms  of  cyclic  derivatives,  also 
form  anhydrides  by  the  same  treatment,  but  isophthalic 
acid  gives  no  inner  anhydride. 


72  ORGANIC   CHEMISTRY. 

Amides  may  be  prepared  in  many  cases  by  heating 
ammonium  salts  of  acids. 

O  O 

#  s 

RC— ONH4  =  R— C— NH2  +  H2O. 
Another  method,   which  is  applicable   in  almost  all 
cases  where  the  resulting  amide  is  difficultly  soluble  in 
water,  consists  in  treating  the   acid  with  phosphorus 
pentachloride  to  convert  it  into  its  chloride,  and  then 
adding  the  mixture  of  the  chloride  with  phosphorus  oxy- 
chloride  carefully  to  cold  concentrated  aqueous  ammo- 
nia,  or  ammonia  gas  may  be  passed  into  the  mixture, 
diluted  with  benzene,  ether,  or  chloroform. 
O  O 

s  s 

RC— Cl  +  2NH3  =  R— C— NHa  +  NH4C1. 
Esters,  on  treatment  with  ammonia,  are  converted  into 
amides  : 

O  O 

S  S 

R— C— OR'  +  NH3  =  R— C— NH3  +  R'— OH. 

This  method  is  seldom  used,  except  in  cases  where 
other  methods  fail.  (See  Kinhorn  and  Bull:  Ann.  Chem. 
(Liebig),  295,  207.) 

The  preparation  of  amides  from  nitriles  or  cyanides 
has  been  referred  to  on  p.  4. 

Acids  which  form  inner  anhydrides  form  also  imides 
in  which  the  NH  group  takes  the  place  of  the  oxygen 
atom  which  completes  the  ring  in  the  case  of  the  anhy- 
dride. These  imides  may  be  prepared  by  heating  the 
ammonium  salt  of  the  acid  : 


DERIVATIVES   OF   ACIDS.  73 

=  R<cC>NH + NH» + H>°- 

In  some  cases  the  ammonium  salt  of  the  half  amide 
of  the  acid  gives  better  results.  The  conversion  of  an 
anhydride  into  an  imide  by  the  action  of  ammonia  prob- 
ably depends  on  the  intermediate  formation  of  such  a 
salt: 

R<CO>°+  2NH3=R<CO-ONH4=R<CO>NH 
+  NH3+H90. 

Closely  related  to  the  amides  are  anilides  and  similar 
compounds,  which  may  be  considered  either  as  amides 
having  a  hydrogen  atom  of  the  NH2  group  replaced  by 
a  hydrocarbon  residue,  or  as  an  amine  having  a  hydro- 
gen atom  of  the  amine  group  replaced  by  an  acid  radi- 
cal. Anilides  and  similar  compounds  may  frequently 
be  prepared  by  simply  heating  the  acid  with  the  amine, 
water  being  eliminated  more  easily  than  in  the  case  of 
the  ammonium  salts. 

RCOOH  +  R'NH,  =  R  —  CO  —  NHR'  +  H2O. 

A  more  general  method  consists  in  treating  the  amine 
with  the  chloride  or  anhydride  of  the  acid,  either  directly, 
or  in  the  presence  of  an  aqueous  solution  of  sodium  hy- 
droxide. ( "  Schotten-Baumann  reaction,''  see  26,  p.  86.) 

Esters  of  strong  acids  may  be  prepared  by  bringing 
together  the  acid  and  alcohol.  The  action  is  aided  by 
heat.  The  reaction  is,  however,  a  reversible  one  and 
proceeds  only  till  an  equilibrium  is  established  between 
the  amounts  of  ester,  water,  alcohol,  and  acid  present. 


74  ORGANIC   CHEMISTRY. 

For  equivalent  weights  of  acid  and  alcohol,  the  per 
cent,  of  ester  formed,  when  equilibrium  is  reached,  is 
characteristic  of  the  acid  and  alcohol  in  question,  and 
varies  greatly  in  different  cases.  Primary  alcohols  form 
esters  more  quickly  and  in  larger  amount  than  second- 
ary, and  secondary  than  tertiary.  In  a  similar  manner 
acids  with  a  primary  carboxyl  (R — CH,CO2H)  form  es- 
ters more  quickly  than  those  with  secondary  carboxyl, 
and  the  latter  more  quickly  than  those  with  a  tertiary 
carboxyl.  These  facts  may  be  used  to  determine  the 
structure  of  the  alcohols  and  acids  (Menschutkin,  see 
third  edition  of  Beilstein  I,  218  and  389). 

The  amount  of  an  acid  which  will  be  converted  into 
an  ester  is  increased  by  the  use  of  a  larger  amount  of 
the  alcohol,  in  accordance  with  the  law  of  mass  action, 
which  applies  to  all  reversible  processes,  that  the  in- 
crease of  the  amount  of  one  of  the  reacting  bodies  in- 
creases the  amount  of  the  product  or  products  (in  this 
case  ester  and  water)  which  result  from  its  action  on 
other  substances  present.  It  follows  that  an  excess  of 
the  alcohol  should  be  used  when  the  acid  is  rare  or  expen- 
sive, and  an  excess  of  the  acid  when  the  alcohol  is  valuable. 

In  most  cases  esterification  is  very  much  hastened  by 
the  addition  of  hydrochloric  or  sulphuric  acid  to  a  mix- 
ture of  an  organic  acid  and  alcohol.  It  was  formerly  sup- 
posed to  be  necessary  to  saturate  the  mixture  with  dry 
hydrochloric  acid  gas,  but  Bmil  Fischer  has  recently 
shown  (Ber.  d.  chem.  Ges.,  28,  3252),  that  a  compar- 
atively small  amount  of  hydrochloric  or  sulphuric  acid 
may  frequently  be  used  with  better  advantage. 


DERIVATIVES   OP   ACIDS.  75 

Ksters  may,  in  most  cases,  be  readily  prepared  from 
the  chlorides  of  acids  by  treatment  with  an  alcohol. 
(SeeBaeyer:  Ann.  Chem.  (L,iebig),  245,  140.) 

O  O 

/  / 

R  —  C  —  Cl  +  R'  —  O  —  H  =  RC  —  OR'  +  HCl. 

They  may  also  be  prepared  by  treating  a  silver  salt 
of  an  acid  with  an  alkyl  iodide, 

O  O 

/  / 

R  —  C  —  OAg  +  R'l  =  R  —  C  —  OR'  +  Agl. 


Halogen  derivatives  of  acids  are  prepared  by  treating 
the  acid,  or,  in  many  cases,  either  the  chloride  or  bro- 
mide of  the  acid,  with  the  free  halogen.  Unless  the 
temperature  is  unduly  raised  so  as  to  cause  secondary 
reactions,  aliphatic  acids  give  by  this  treatment  only  a 
derivatives.  (Erlenmeyer :  Ber.  d.  chem.  Ges.,  14, 
1318  ;  Hell :  Ibid,  14,  891  ;  Auwers  :  Ibid,  24,  2209, 
2233  ;  Michael :  J.  prakt.  Chem.  [2],  36,  92  ;  Volhard  : 
Ann.  Chem.  (L,iebig),  242,  161.) 

3Cn  H2n+I  CO,H  +  P  +  i  iBr  =  3Cn  H2nBrCOBr  + 
HP03  +  5HBr. 

ft  derivatives  may  usually  be  obtained  by  treating 
aft  unsaturated  acids  with  the  halogen  acids.  Bisubsti- 
tution  products  are  obtained  by  the  addition  of  the  free 
halogen  to  unsaturated  acids. 

The  direct  treatment  of  aromatic  acids  with  halogens 
gives  chiefly  meta  compounds. 


76  ORGANIC   CHEMISTRY. 

Hydroxy  acids  (frequently  called,  in  accordance  with 
historic  nomenclature,  oxy  acids)  ,  are  prepared,  in  the 
aliphatic  series,  by  treating  halogen  derivatives  with  sil- 
ver oxide  or  with  alkalies,  or  by  treating  amino  acids 
with  nitrous  acid.  The  latter  method  is  also  useful  in 
the  aromatic  series.  Other  aromatic  hydroxy  acids  are 
obtained  either  by  Kolbe's  (see  36,  p.  101)  or  Reimer-Tie- 
mann's  reactions  (Ber.  d.  chem.  Ges.,  9,  423,  824;  10, 
63,  213)  ,  or  by  fusion  of  sulphonic  or  halogen  derivatives 
with  caustic  potash  : 


R      +  KOH  =  R      +  KNaSO- 


Cyclic  acids  derived  from  the  aromatic  acids  have 
been  obtained  by  the  reduction  of  the  latter  with  sodium 
amalgam,  or  with  amyl  alcohol  and  sodium.  The  same 
acids  have,  in  several  cases,  been  prepared  from  aliphatic 
compounds  by  methods  of  condensation. 

Hydrogen  may  be  added  to  many  unsaturated  acids 
by  reduction  with  sodium  amalgam. 


20.  Preparation  of  an  Acid  Chloride. — Acetyl  chlo- 
ride, CH3.COC1.  (Ethanoyl  chloride.) 

Literature. — Be"champ  :  Jsb.  d.  Chem.,  /#55,  504 ;  1856,  427  ; 
J.  prakt.  Chem.,  65, '495;  Thorpe:  J.  Chem.  Soc.,  1880,  37,  186; 
Bothamley,  Thompson  :  Chem.  News,  1890,  62,  191 ;  Gerhardt : 
Ann.  Chem.  (Liebig),  87,  63. 

i oo  grams  acetic  acid  (glacial). 
80  grams  phosphorus  trichloride. 

Arrange  a  300  cc.  distilling  bulb,  condenser  and  re- 
ceiver as  indicated  in  Fig.  16. 


DERIVATIVES   OF   ACIDS.  77 

All  of  the  apparatus  must  be  absolutely  dry,  and  the 
side  tube  of  the  receiver  should  be  connected  with  a 
tube  which  will  deliver  the  hydrochloric  acid  evolved 
immediately  over  the  surface  of  some  water  in  a  bottle. 
Place  in  the  distilling  bulb  100  grams  (96  cc.)  of  glacial 
acetic  acid,  and  add  through  the  dropping  funnel  80 
grams  of  phosphorus  trichloride.  Warm  for  a  short 


Fig.  16. 

time,  gently,  till  the  evolution  of  hydrochloric  acid 
nearly  ceases  and  the  liquid  separates  in  two  layers. 
Then  distil  from  a  water-bath  as  long  as  anything  comes 
over.  The  distillate  usually  contains  some  phosphorus 
trichloride.  If  a  product  entirely  free  from  phosphorus 
is  required,  add  two  or  three  grams  of  powdered,  dry, 
sodium  acetate,  allow  to  stand  over  night,  and  distil 
again  from  the  water-bath,  collecting  the  portion  boiling 
at  50°-56°.  Yield  80  to  90  grams. 

Acetyl  chloride  is  a  colorless  liquid  with  a  very  disa- 


78  ORGANIC   CHEMISTRY. 

greeable  odor.  It  boils  at  50.9°,  and  has  a  specific 
gravity  of  1.1051  at  20°.  It  decomposes  rapidly  with 
water  or  moist  air  and  must  be  kept  in  tightly  closed, 
glass-stoppered  bottles. 

Acetyl  chloride  reacts  readily  with  almost  all  bodies 
containing  either  an  alcoholic  hydroxyl,  or  an  amine 
group.  In  both  cases  a  hydrogen  atom  of  the  group  is 
replaced  by  the  acetyl  group,  C2H3O.  The  resulting 
compounds  are,  in  many  cases,  crystalline  and  difficultly 
soluble  in  water,  and  hence  well  adapted  for  the  charac- 
terization of  bodies  of  these  two  classes. 

21.  Preparation  of  an  Anhydride  of  an  Acid. — Acetic 

O     O 

/       \ 
anhydride,  CH3C— O— C— CH3.   (Kthanoic  anhydride.) 

Literature.— Gerhardt :  Ann.  Chem.  (Liebig),  (1852},  82,  131; 
87,  149. 

60  grams  dry  sodium  acetate. 

50  grams  acetyl  chloride. 

Place  in  a  dry,  200  cc.  flask,  60  grams  of  freshly  fused 
dry,  powdered  sodium  acetate,  and  connect  with  an  up- 
right condenser. 

Add,  in  small  portions,  through  the  condenser,  50 
grams  of  acetyl  chloride,  shaking  vigorously  after  each 
addition.  Warm  on  a  water-bath  as  long  as  any  acetyl 
chloride  condenses  and  runs  back.  Then  connect  the 
flask  with  the  condenser  in  the  usual  manner  by  means 
of  rubber  stoppers  and  a  bent  tube,  and  distil  slowly 
with  a  free  flame,  holding  the  burner  in  the  hand.  Collect 
the  portions  boiling  at  130°- 142°.  Add  to  the  distillate 


DERIVATIVES   OF   ACIDS.  79 

two  or  three  grams  of  dry  sodium  acetate  and  distil 
again.  Yield  40  to  50  grams. 

Acetic  anhydride  is  a  colorless  liquid  with  an  un- 
pleasant odor.  It  boils  at  138°,  and  has  a  specific 
gravity  of  1.08  at  15°. 

With  most  bodies  containing  alcoholic  or  amine 
groups  acetic  anhydride  reacts,  giving  the  same  prod- 
ucts as  acetyl  chloride.  The  reaction  is  usually  less 
violent,  and,  of  course,  no  hydrochloric  acid  is  formed. 
Since  acetic  anhydride  does  not  react  very  quickly  with 
cold  water,  it  may  be  used  for  the  Schotten-Baumann 
reaction  (26  and  30,  pp.  86,91),  while  acetyl  chloride 
cannot. 

22.  Preparation  of  the  Anhydride  of  a  Bibasic  Acid. 


—  Succinic   anhydride, 


CH.-C 

^O. 

CH'~<o 


Literature.—  Gerhard!  u.  Chiozza  :  Ann.  Chem.  (Liebig),  87, 
293  ;  Anschiitz  :  Ber.  d.  chem.  Ges.,  10,  1883  ;  Ann.  Chem.  (Lie- 
big),  226,  8  ;  Volhard  :  Ibid,  242,  150  ;  Auwers  :  Ibid,  285,  223. 

20  grams  succinic  acid. 

13  grams  phosphorus  oxychloride. 

Place  in  a  small  flask  20  grams  (2  mols.)  of  dry  suc- 
cinnic  acid.  Add  13  grams  (i  mol.)  of  phosphorus  oxy- 
chloride. Connect  with  an  upright  condenser,  and  warm 
gently  on  an  asbestos  plate  so  long  as  hydrochloric  acid 
escapes.  To  avoid  the  escape  of  the  acid  into  the  room 
connect  the  top  of  the  condenser  with  a  tube  which  will 


80  ORGANIC   CHEMISTRY. 

deliver  the  gas  just  above  the  surface  of  water  in  a  bot- 
tle. When  acid  ceases  to  escape,  transfer  to  a  50  cc. 
distilling  bulb,  connect  with  an  air  condensing  tube,  and 
distil.  When  the  drops  coming  over  solidify  easily,  re- 
move the  condensing  tube  and  distil  slowly  into  a  small 
flask  without  any  condenser.  Crystallize  the  anhydride 
from  chloroform.  Yield  almost  quantitative. 

Instead  of  phosphorus  oxy chloride,  12  grams  of  phos- 
phorus pentachloride  may  be  used  but,  in  that  case,  the 
mixture  should  be  warmed  on  the  water-bath  till  it  be- 
comes liquid  before  placing  it  on  the  asbestos  plate  over 
the  free  flame. 

Succinic  anhydride  crystallizes  from  chloroform  or 
acetic  anhydride  in  needles,  which  melt  at  119.6°.  It 
boils  at  261°.  It  may  also  be  crystallized  from  absolute 
alcohol,  but  on  boiling  for  some  time  with  absolute  alco- 
hol it  is  converted  into  the  mono-ethyl  ester  of  succinic 
acid. 

23.  Preparation  of  an  Amide  by  Heating  the  Ammo- 
nium Salt  of  an  Acid.  Acetamide,  CH3— CONH2. 

Literature. — Letts  :  Ber.  d.  chem.  Ges.,  5,  669;  Hofmann  : 
Ibid,  15,  978  ;  v.  Nencki,  Leppert :  Ibid,  6,  903  ;  J.  Schultze  :  J. 
prakt.  Chem.,  (1883),  N.  F.,  27,  514. 

50  grams  glacial  acetic  acid. 

55  to  60  grams  ammonium  carbonate. 

Warm  50  grams  of  glacial  acetic  acid  gently  in  a  por- 
celain dish  and  add  powdered  ammonium  carbonate  till 
a  little  of  the  mixture,  on  dilution  with  water,  shows  an 
alkaline  reaction  with  litmus.  Prepare  two  sealing 
tubes  about  2  to  2.5  centimeters  in  internal  diameter, 


DERIVATIVES  OF   ACIDS.  8 1 

and  with  walls  2  to  3  mm.  thick.  In  closing  the  ends 
of  the  tubes,  and  also  in  sealing  after  they  have  been 
filled,  the  glass  must  be  so  thoroughly  softened  as  to 
sink  together  somewhat,  and  must  not  be  drawn  so 
rapidly  as  to  become  thin  at  any  point.  Warm  the 
sealing  tubes  gently  over  the  flame,  and  heat  the 
ammonium  acetate  till  it  becomes  liquid.  Transfer  it  to 
the  tubes,  using  a  thistle  tube  or  funnel  with  a  long  stem 
so  that  the  tubes  are  not  wet  near  the  point  where  they 
are  to  be  sealed.  The  tubes,  when  sealed,  should  not 
be  more  than  three-fourths  full.  Seal  the  tubes  care- 
fully, and  when  cold  put  them  in  a  bomb-oven  and  heat 
for  five  hours  at  22o°-23o°.  Cool.  Open  the  tubes  and 
transfer  the  mixture  to  a  distilling  bulb  and  subject  it 
to  fractional  distillation,  using  an  air  condensing  tube 
(see  i*  p.  15).  Collect  the  portion  boiling  at  i8o°-23o°  in 
a  beaker.  Cool  thoroughly,  and  spread  on  porous  por- 
celain to  remove  liquid  impurities.  The  portion  re- 
maining will  be  nearly  pure  acetamide.  The  pure  com- 
pound may  be  obtained  by  crystallization  from  benzene. 
Yield  about  25  grams. 

Pure  acetamide  consists  of  colorless,  odorless,  rhom- 
bohedral  crystals,  which  melt  at  82°.  It  boils  at  222°. 
It  is  easily  soluble  in  alcohol  and  in  water,  difficultly 
soluble  in  ether  and  benzene. 

Acetamide  is  easily  saponified  by  alkalies.  It  is  con- 
verted into  methylcyanide  (acetonitrile)  by  warming  for 
a  short  time  with  phosphorus  pentoxide  and  distilling. 
An  aqueous  solution  of  acetamide  dissolves  mercuric 
oxide  with  the  formation  of  the  compound 
(CH3CONH)2Hg. 


82  ORGANIC   CHEMISTRY. 

The  hydrogen  of  the  amido  group  may  also  be  replaced 
by  bromine  or  by  other  halogen  atoms.  Acetamide 
forms  unstable  salts  with  hydrochloric  acid  and  with 
nitric  acid. 

24.  Preparation  of  an  Amide  from  the  Chloride  of  an 

Acid.—  Urea,  CO<9,  Carbamide. 


Literature.—  Wohler  :  Berz.  Jsb.,  12,  266  (1828}  ;  Natanson  : 
Ann.  Chem.  (Iviebig),  98,  289;  Basarow  :  J.  prakt.  Chem.  [2],  x, 
283;  Mixter:  Am.  Chem.  J.,  4,  35  ;  Millon  :  [2]  8,  235;  Schmidt: 
Ber.  d.  chem.  Ges.,  10,  193;  Duggan  :  Am.  Chem.  J.,  4»  47  ; 
Schmidt  :  Ztschr.  anal.  Chem.,  i,  242. 

10  cc.  solution  of  phosgene  in  toluene  (20  per  cent)  . 

15  cc.  ammonia  (0.96). 

Put  in  a  small  flask  15  cc.  of  ammonia  and  add  in 
three  or  four  portions,  shaking  and  cooling  after  each 
addition,  10  cc.of  a  twenty  per  cent,  solution  of  carbonyl 
chloride,  COC13,  in  toluene.  The  solution  should  now 
react  alkaline.  Pour  the  mixture  into  a  porcelain  dish, 
and  evaporate  to  dry  ness  on  the  water-bath.  Put  the 
residue  into  a  dry  test-tube,  add  about  10  cc.  of  alcohol, 
and  boil.  Cool,  pour  off  through  a  filter,  and  repeat  the 
same  treatment  twice.  Evaporate  the  alcoholic  solu- 
tion to  dry  ness.  The  residue  will  now  consist  mainly  of 
urea  with  a  little  ammonium  chloride.  About  one  gram 
should  be  obtained.  Crystallize  from  a  little  amyl  alco- 
hol. 

Urea  crystallizes  in  long  prisms  or  thick  needles.  It 
melts  at  132°.  It  is  easily  soluble  in  water.  100  parts 
of  alcohol  dissolve  5.06  parts  at  19.5°.  From  not  too  di- 


DERIVATIVES   OF   ACIDS.  83 

lute  aqueous  solutions  it  is  precipitated  in  the  form  of 
the  nitrate,  CO^-TT'TT-NT     >  on  the  addition  of  nitric 


acid.     The   nitrate  is  very  difficultly  soluble   in  nitric 
acid,  and  is  converted  into  nitrourea, 


cold  concentrated  sulphuric  acid.  (See  77.)  Urea 
forms  double  compounds  with  many  salts  and  metal- 
lic oxides,  and,  also,  compounds  in  which  its  hydrogen  is 
replaced  by  metals.  It  is  decomposed  by  alkaline  hypo- 
bromites  with  liberation  of  nitrogen,  a  property  used  for 
its  quantitative  determination. 

Concentrated  solutions  of  alkalies  decompose  it  on 
boiling,  with  the  formation  of  a  carbonate  and  ammonia. 
Acids  decompose  it  more  rapidly. 

25.  Preparation  of  an  Amide  by  Means  of  Phos- 
phorus Pentachloride  and  Ammonia.  —  Phenyl  sulphon- 
amide,  C6H6SO3NHa. 

Literature.—  Mitscherlich  :  Ann.  der  Phys.  (Pogg.)  31,  283,  631  ; 
Stenhouse  :  Ann.  Chem.  (Liebig),  140,  284;  Gattermann  :  Ber. 
d.  chem.  Ges.,  24,  2121  ;  Michael,  Adair  :  Ber.  d.  chem.  Ges., 
I0>  585  ;  Gerhardt,  Chancel  :  J.  i8$2>  434  ;  v.  Meyer,  Ador  :  Ann. 
Chem.  (Liebig),  159,  n  ;  Hybbeneth  :  Ibid,  221,  206. 

loo  cc.  fuming  sulphuric  acid  (sp.  gr.  1.87). 

50  cc.  benzene. 

350  cc.  water. 

50  grams  acid  sodium  carbonate. 

100  grams  salt. 

20  grams  crude  sodium  benzene  sulphonate. 

20  grams  phosphorus  pentachloride. 

70  cc.  ammonia  (sp.  gr.  0.90). 


84  ORGANIC   CHEMISTRY. 

To  100  cc.  of  fuming  sulphuric  acid,  containing  5  to  8 
percent,  of  the  anhydride  (sp.  gr.  1.87  at  15°) ,  in  a  300  cc. 
flask,  add,  in  small  portions,  50  cc.  of  benzene,  shaking 
vigorously  after  each  addition  and  keeping  the  tempera- 
ture below  50°  by  occasional  cooling.  When  the  ben- 
zene has  all  dissolved,  pour  slowly  into  350  cc.  of  water, 
cool,  and  filter  from  any  diphenyl  sulphone,  (C6HB)2SO2, 
which  separates.  Partly  neutralize  the  acid  by  adding, 
carefully,  50  grams  of  acid  sodium  carbonate  (baking 
soda),  then  add  100  grams  of  common  salt,  warm  till  it 
dissolves,  filter  and  cool,  with  stirring.  As  soon  as  the 
sodium  benzene  sulphonate  has  separated  completely, 
filter  on  a  plate  and  suck  dry.  Moisten  with  a  saturated 
solution  of  salt  and  suck  dry  again.  Dry  the  salt  on  a 
plate  of  porous  porcelain.  Yield  40  to  50  grams  of  the 
salt.  The  salt  can  be  crystallized  from  alcohol  if  de- 
sired, but  is  already  pure  enough  for  most  purposes. 

Place  in  a  100  cc.  flask  20  grams  of  phosphorus  penta- 
chloride  (weigh  in  the  hood  and  avoid  exposure  to  the 
air  as  far  as  possible),  add  20  grams  of  crude  sodium 
benzene  sulphonate,  dried  at  120°,  close  the  flask  with 
a  perforated  rubber  stopper  bearing  a  tube  which  will 
deliver  the  hydrochloric  acid  evolved  just  above  the  sur- 
face of  water  in  a  bottle  or  flask.  Warm  on  the  water- 
bath  as  long  as  hydrochloric  acid  is  evolved.  Cool.  Pour 
the  contents  of  the  flask,  in  small  portions,  into  70  cc. 
of  ammonia  (0.90  sp.  gr.)  contained  in  a  200  cc.  flask, 
cooling  thoroughly  after  each  addition.  Filter,  wash 
with  cold  water,  and  crystallize  from  hot  water  or  from 
dilute  alcohol.  Yield  12  to  15  grams. 


• 
DERIVATIVES   OF  ACIDS.  85 

If  benzene  sulphonchloride  is  desired,  the  liquid  prod- 
uct obtained  by  the  action  of  the  pentachloride  on  sodium 
benzene  sulphonate  may  be  poured  in  small  portions  into 
200  cc.  of  cold  water,  and  shaken  with  the  latter  for 
some  time  to  decompose  the  phosphorus  oxy chloride, 
the  sulphonchloride  taken  up  with  ether,  and  after  dry- 
ing with  -calcium  chloride  and  distilling  off  the  ether, 
distilled  under  diminished  pressure. 

Benzene  sulphonchloride  melts  at  14.5°  and  boils  with 
decomposition  at  246°.  Under  10  mm.  pressure  it  boils 
at  120°.  It  has  a  specific  gravity  of  1.378  at  23°. 

It  may  be  used  to  distinguish  the  three  classes  of 
amines  (Hinsberg:  Ber.  d.  chem.  Ges.,  23,  2965). 
With  primary  amines  it  gives  alkyl-sulphonamides, 
CBH5SO2NHR,  which  are  soluble  in  alkalies,  with  sec- 
ondary amines  it  gives  dialkyl-sulphonamides  C6H6SO, 
NRR',  which  are  insoluble  in  alkalies,  and  with  tertiary 
amines  it  does  not  react.  The  compounds  with  primary 
and  secondary  amines  may  usually  be  prepared  by  the 
Schotten-Baumann  reaction. 

Benzene  sulphonamide  crystallizes  in  needles  from 
water,  or  in  leaflets  from  alcohol.  Both  melt  at  147°- 
148°.  (Hybbeneth  gives  156°.)  It  is  easily  soluble  in 
alcohol  and  ether,  difficultly  soluble  in  cold  water.  The 
hydrogen  of  the  amide  group  can  be  replaced  by  metals, 
hence  the  sulphonamides  are  soluble  in  alkalies,  and 
some  of  them  are  quite  soluble  in  a  solution  of  sodium 
carbonate. 

26.    Preparation   of  the   Benzoyl   Derivative    of    a 


86  ORGANIC    CHEMISTRY. 

Phenol — Schotten-Baumann  Reaction. — Phenyl  benzo- 
O 

ate,  CeH5— C-0  — C6H6. 

Literature.— Baumann  :  Ber.  d.  chem.  Ges.,  ig,  3218  ;  Udrans- 
zky  &  Baumann  :  Ibid,  ax,  2744  ;  Hinsberg  :  Ibid,  23,  2962  ;  Schot- 
ten  :  Ibid,  17,  2545. 

Dissolve  about  one-half  gram  of  phenol  in  5  cc.  of 
water,  add  three-fourths  gram  of  benzoyl  chloride  and  a 
little  caustic  soda,  enough  so  that  the  solution  remains 
alkaline  after  warming,  and  shaking,  till  the  odor  of  ben- 
zoyl chloride  has  disappeared.  On  cooling  and  stand- 
ing the  phenyl  benzoate  solidifies,  and,  after  filtering  off 
and  washing,  may  be  crystallized  from  a  little  alcohol. 
It  melts  at  69°. 

This  reaction,  which  is  generally  applicable  to  alco- 
hols, phenols,  and  to  primary  and  secondary  amines, 
and  in  which  acetic  anhydride,  sulphonchlorides  and 
other  similar  compounds  may  be  used  instead  of  benzoyl 
chloride,  is  especially  useful  in  converting  liquid  or 
easily  soluble  bodies  into  solid,  difficultly  soluble  deriv- 
atives for  purposes  of  identification. 

27.  Preparation  of  an  Acid  Derivative  of  an  Amine. 

— Acetanilide,  C6H6NH.C2H9O. 

Literature.— Gerhardt :  Ann.  Chem.  (L,iebig),  87,  164  ;  Wil- 
liams :  Ibid,  131,  288;  Witt:  Dissertation,  (Zurich,  1875),  12; 
J.  Chem.  Soc.,  17,  106,  (1864). 

25  grams  aniline. 

35  grams  glacial  acetic  acid. 

Put   in   a   200  cc.   flask  25  grams  of  aniline  and  35 


DERIVATIVES  OF    ACIDS.  87 

grams  of  glacial  acetic  acid.  Place  in  the  mouth  of  the 
flask  a  stopper  bearing  a  tube  one  cm.  in  diameter  and 
50  cm.  long.  Heat  on  a  thin  asbestos  paper  on  a  wire 
gauze,  and  adjust  the  flame  so  that  the  vapors  of  acetic 
acid  condense  about  two- thirds  of  the  way  up  the  tube. 
As  water  is  formed  during  the  reaction,  it  will  gradually 
escape  from  the  to'p  of  the  tube,  and  this  hastens  the  re- 
action. If  the  apparatus  cannot  be  conveniently  placed 
in  a  hood  the  top  of  the  tube  should  be  bent  over,  and  a 
flask  placed  under  it  to  collect  the  dilute  acid  which  es- 
capes. After  boiling  for  4  to  5  hours,  pour  carefully, 
with  stirring,  into  400  cc.  of  water,  filter  when  cold,  and 
recrystallize  from  hot  water,  dilute  alcohol,  or  from  ben- 
zene. Yield  about  80  per  cent,  of  the  theory. 

Acetanilide  (known  in  medicine  as  antifebrin)  melts 
at  1 1 6°,  and  boils  at  304°.  It  dissolves  in  189  parts 
of  water  at  6°.  It  is  easily  soluble  in  hot  water,  alcohol, 
ether,  and  benzene.  It  may  be  saponified  either  by  boil- 
ing with  caustic  potash  or  concentrated  hydrochloric 
acid. 

28.  Preparation   of  an    Ester. — Ethyl   acetic    ester, 

O 
/ 

(Acetic  ether)  CH3C— OCaHB.   (Ethyl  Ester  of  Ethanoic 

Acid.) 

Literature.— Geuther  :  Jsb.  d.  chem.,  1863,  323 :  Frankland, 
Duppa  :  Ann.  Chem.  (Iviebig),  138,205;  Markownikoff :  Ber.  d. 
chem.  Ges.,  6,  1177;  Pabst :  Bull.  Soc.  Chim.,  33.  35°. 

25  cc.  alcohol. 

25  cc.  concentrated  sulphuric  acid. 


88  ORGANIC   CHEMISTRY. 

200  cc.  alcohol. 

200  cc.  glacial  acetic  acid. 

Place  in  a  250  cc.  distilling  bulb  25  cc.  of  alcohol,  and 
25  cc.  of  concentrated  sulphuric  acid.  Put  in  the  mouth 
of  the  bulb  a  stopper  bearing  a  separatory  funnel,  the 
stem  of  which  reaches  nearly  to  the  bottom  of  the  bulb, 
and  a  thermometer  which  dips  in  the  mixture.  Con- 
nect with  a  condenser  and  heat  carefully  to  130°-  135°. 
Run  in  slowly  a  mixture  of  200  cc.  of  glacial  acetic  acid 
and  200  cc.  of  alcohol,  regulating  the  flow  and  the  flame 
so  that  the  temperature  remains  at  about  135°.  Shake 
the  distillate  in  a  flask  with  a  sodium  carbonate  solution 
till  it  no  longer  reacts  acid,  separate  the  aqueous  solu- 
tion by  means  of  a  separatory  funnel,  add  a  solution  of 
50  grams  of  calcium  chloride  in  50  grams  of  water, 
shake,  and  separate  again,  to  remove  alcohol  which  it 
contains.  Dry  the  acetic  ether  by  allowing  it  to  stand 
over  night  with  a  little  fused  calcium  chloride,  and  frac- 
tionate. The  portion  boiling  at  72°—  78°  is  nearly  pure. 
For  use  in  the  preparation  of  acetacetic  ether  it  should 
be  allowed  to  stand  a  day  with  one-fifth  of  its  weight  of 
granular  calcium  chloride  and  filtered.  Yield  80  to  90 
per  cent,  of  the  theory. 

Acetic  ester  boils  at  77°,  and  has  a  specific  gravity  of 


o 


0.9239   at  --,  and  of  0.8300  at  --  .      It  dissolves  in 

4  4 

17  parts  of  water  at  17.5°,  28  parts  of  the  ester  dissolve 
one  part  of  water.  It  is  easily  saponified  by  boiling 
with  alkalies,  and  is  slowly  saponified  by  merely  stand- 
ing with  water. 


DERIVATIVES   OF   ACIDS.  89 

29.  Preparation   of  an    Ester  of  a  Bi  basic  Acid.  — 

CH.CO.C.H. 

Ethyl  succinic  ester,    | 

CH.COAH. 

Literature.  —  Weger  :  Ann.  Chem.  (Liebig),  221,  89;  Fehling: 
Ibid,  49,  186,  195;  Perkin:  J.  Chem.  Soc.,  45>  5*5  (^84)  ; 
Crum  Brown,  Walker  :  Ann.  Chem.  (Liebig),  261,  115. 

100  grams  succinic  acid. 

170  cc.  alcohol. 

5  cc.  concentrated  sulphuric  acid. 

In  a  300  cc.  flask  put  100  grams  of  succinnic  acid,  170 
cc.  of  alcohol,  and  5  cc.  of  concentrated  sulphuric  acid. 
Heat  for  two-hours  on  a  water-bath  with  an  upright 
condenser  or  condensing  tube.  Cool,  and  pour  into  a 
large  flask  containing  25  grams  of  sodium  bicarbonate 
and  150  of  water.  Shake  thoroughly,  and  separate  the 
ester.  Wash  it  once  with  a  little  water,  dry,  as  directed, 
formalonic  ester  (see  7,  p.  36),  and  fractionate.  Yield 
good. 

Succinic  ethyl  ester  boils  at  2i7°-2i8°,  and  has  a  speci- 
fic gravity  of  1.0475  at  25.5°. 

30.  Preparation  of  the  Ester  of  a  Hydroxy  Acid  and 
of  an  Acetyl  Derivative.—  Di-acetyl  tartaric  ethyl  ester, 

C02C,H6 

CH—  OC2H3O 
CH—  OCH0 


83 


Literature.  —  Landolt;    Ann.  Chem.   (Liebig),    189,   324;    An- 
schiitz  :  Ber.  d.  chem.  Ges.,  18,  1399;  Wislecenus:  Ann.  Chem. 


90  ORGANIC   CHEMISTRY. 

(Liebig),  129,  184;  Perkin  :    A  Supl.,  5,  285  ;   J.  Chem.  Soc.,  51, 
369  (1887") ;  K.  Fischer:  Ber.  d.  chem.  Ges.,  28,  3255. 

25  grams  tartaric  acid. 

120  cc.  absolute  alcohol. 

i  gram  hydrochloric  acid  gas. 

Put  25  grams  of  tartaric  acid  in  a  200  cc.  distilling 
bulb,  add  120  cc.  of  absolute  alcohol,  and  pass  into  the 
bulb  about  one  gram  of  hydrochloric  acid  gas.  The  gas 
may  be  generated  in  a  small  flask  from  salt  and  concen- 
trated sulphuric  acid  diluted  with  one-fourth  of  its  volume 
of  water,  or  by  dropping  concentrated  sulphuric  acid  into 
commercial  hydrochloric  acid,  and  the  amount  can  be  de- 
termined by  placing  the  bulb  in  a  beaker  on  one  pan  of  a 
balance ,  which  is  sensitive  to  about  one-tenth  gram .  Close 
the  side  tube  of  the  bulb  with  a  bit  of  rubber  tubing  and 
a  glass  rod,  and  place  in  the  mouth  of  the  bulb  a  stop- 
per and  tube  to  act  as  an  air  condenser.  Heat  for  2  to  3 
hours  on  a  water-bath,  inclining  the  bulb  in  such  a 
manner  that  the  vapors  which  condense  in  the  side  tube 
will  run  back  into  the  bulb.  Adjust  a  capillary  tube 
and  stopper,  and  a  second  bulb  to  collect  the  distillate,  as 
on  p.  46,  and  distil  the  excess  of  alcohol  and  the  water 
formed  under  gradually  diminishing  pressure,  and  finally 
dry  for  fifteen  minutes  under  as  low  a  pressure  as  can  be 
secured  and  with  the  bulb  immersed  in  a  boiling  water- 
bath.  Add  80  cc.  of  absolute  alcohol,  and  i  gram  of 
hydrochloric  acid,  and  heat  as  before  with  an  air  con- 
denser for  two  hours.  By  the  removal  of  the  water 
formed  by  the  esterification,  and  a  second  treatment  with 
fresh  alcohol  a  much  more  complete  conversion  can  be 


DERIVATIVES   OF   ACIDS.  91 

secured.  Distil  the  alcohol  and  water  as  before  and 
then  distil  from  an  oil-bath  or  with  the  free  flame  under 
as  low  a  pressure  as  can  be  secured  and  with  a  ther- 
mometer (see  p.  46).  The  portion  boiling  at  i6o°-i8o° 
under  30  mm.  pressure  will  consist  of  nearly  pure  di- 
ethyl  tartaric  ester.  Yield  23-26  grams. 
The  ester  boils  at 

280°  under  a  pressure  of  760  mm. 
232°      "  "         "  197     " 

162°      "  "         "     19     " 

157°      "  "         "     ii     " 

It  has  a  specific  gravity  of  1.2059  at  20°. 

3  grams  di- ethyl  tartaric  ester. 

5  grams  acetic  anhydride. 

30  cc.  sodium  hydroxide  (10  per  cent.). 

Place  in  a  small  flask  3  grams  of  di-ethyl  tartaric 
ester,  add  five  grams  of  acetic  anhydride  and  then,  in 
small  portions,  with  constant  shaking,  30  cc.  of  a  10  per 
cent,  solution  of  sodium  hydroxide.  As  soon  as  the 
odor  of  the  acetic  anhydride  has  disappeared,  filter  off 
the  acetyl  derivative  if  it  solidifies,  wash  it  with  water 
and  recrystallize  it  from  alcohol,  dissolving  in  a  very  lit- 
tle hot  alcohol,  and  adding  water  till  the  solution  begins 
to  become  turbid. 

If  the  acetyl  compound  fails  to  solidify  at  first  it  will 
usually  do  so  on  standing  in  a  cool  place  for  a  day  or 
two.  If  some  of  the  crystallized  compound  is  at  hand 
the  addition  of  a  crystal  will  be  of  service. 

Di-acetyl  tartaric  ethyl  ester  melts  at  67°,  and  boils  at 


Q2  ORGANIC    CHEMISTRY. 

29i°-292°  under  727  mm.,  or  at  22g°-2^o0  under  100  mm. 
Very  considerable  historical   interest  attaches  to  the 
substance,  because  by  means  of  it  the  structure  of  tar- 
taric  acid  was  first  clearly  established. 

31.  Preparation  of  an  Ester  by  Means  of  Phosphorus 
Pentachloride  and  Alcohol.  —  Benzoic  ethyl  ester, 
C6H6CO,C,H6. 

Literature.— Baeyer  :  Ann.  Chem.  (Liebig),  245,  140;  Liebig : 
Ibid,  65,  351  ;  E.  Fischer,  Speier  :  Ber.  d.  chem.  Ges.,  28,  1150, 
3255. 

10  grams  benzoic  acid. 

21  grams  phosphorus  pentachloride. 

50  cc.  alcohol. 

Put  in  a  small  flask  10  grams  of  benzoic  acid,  and  21 
grams  of  phosphorus  pentachloride.  Connect  with  a 
tube  which  will  deliver  the  hydrochloric  acid  evolved 
just  above  the  surface  of  water  in  a  bottle.  Warm  on  a 
water-bath  till  all  is  liquid.  Cool,  and  pour  carefully 
into  50  cc.  of  alcohol.  Cool  thoroughly,  add  100  cc.  of 
water  and  enough  ether  to  bring  the  benzoic  ester  to  the 
surface.  Separate,  wash  with  a  solution  of  sodium  car- 
bonate to  remove  acid,  dry  the  ethereal  solution  by  al- 
lowing it  to  stand  for  several  hours  with  dry  potassium 
carbonate,  pour  off,  or  filter,  and  distil  from  a  small  dis- 
tilling bulb. 

Other  methods  of  preparing  benzoic  ester  are  more 
suitable,  and  this  method  is  only  given  as  an  illustration 
of  a  method  which  is  quite  generally  applicable.  The 
yield  is  almost  quantitative  if  care  is  used. 


DERIVATIVES  OF   ACIDS. 


93 


Benzole  ester  boils  at  211°,  and  has  a  specific  gravity 
of  1.0502  at  16°. 

32.  Preparation  of  a  Bromine  Derivative  of  an  Acid. 
Hell-Volhard  -  Zelinsky's     Method.  —  a-  Brom-butyric 


Fig.  17. 

acid,  CH3CH2CHBr.CO,H.     Brom-(2)-butanoic  acid. 

Literature. — Borodin:  Ann.  Chem.  (Liebig),  119,  121;  Nau- 
mann:  Ibid,  119,  115;  Hell:  Ber.  d.  chem.  Ges.,  14,891;  ax, 
1726;  Volhard:  Ann.  Chem.  (lyiebig),  242,  141;  Ber.  d.  chem. 
Ges.,  21,  1904;  Zelinsky :  Ibid,  20,  2026;  Auwers  and  Bern- 
hardi:  Ibid,  24,  2216;  Hell  and  L,auber  :  Ibid,  7,  560. 

17.6  grams  butyric  acid. 
2.2  grams  red  phosphorus. 
60  grams  bromine  (2occ.). 


94  ORGANIC   CHEMISTRY. 

Select  a  small  Liebig  condenser  whose  inner  tube  will 
pass  just  inside  of  the  neck  of  a  50  cc.  round-bottomed 
flask.  Cut  off  the  lip  of  the  flask,  put  the  end  of  the  con- 
denser in  its  mouth  and  connect  by  means  of  a  rubber  tube, 
which  slips  over  both,  as  is  done  with  some  forms  of  con- 
densers. (SeeFig.  17.)  Put  in  the  flask  2. 2  grams  (£  at.) 
of  red  phosphorus,  and  17.6  grams  (i  mol.)  of  normal 
butyric  acid.  Add  slowly  from  a  dropping  tube  with  a 
glass  stop-cock,  or  from  a  bulb  drawn  out  to  a  capillary 
below,  through  the  top  of  the  condenser,  60  grams  (*£• 
at.)  of  bromine.  The  bromine  is  best  measured  from 
a  dry  burette  or  measuring  tube,  in  a  good  hood  or  out 
of  doors.  The  top  of  the  condenser  should  be  closed 
with  a  doubly  perforated  stopper,  one  hole  carrying  the 
dropping  tube,  and  the  other  a  tube  leading  out  of  doors 
or  just  over  the  surface  of  a  solution  of  caustic  soda  in 
a  bottle.  Drop  in  the  bromine  slowly,  and  warm  very 
gently  on  a  water-bath  till  the  vapors  of  bromine  disap- 
pear, usually  about  an  hour.  Cool,  and  pour  the  con- 
tents of  the  flask,  in  small  portions,  upon  50  grams  of 
ice  in  a  flask.  Shake  vigorously,  keeping  the  contents 
of  the  flask  cold,  till  the  bromide  of  the  brombutyric 
acid  is  decomposed,  and  the  odor  of  phosphorus  oxy- 
bromide  has  disappeared.  Separate  the  acid  from  the 
aqueous  solution,  wash  it  once  with  a  small  amount  of 
water,  and  distil  it  under  diminished  pressure.  The 
portion  boiling  at  i35°-i4o°,  under  a  pressure  of  35  mm. 
will  be  nearly  pure. 

In  working  with  a  small  amount  of  acid  the  bromi- 
nation  may  be  effected  with  advantage  by  putting  a 


DERIVATIVES   OF   ACIDS.  95 

weighed  quantity  of  the  acid  in  a  sealed  tube,  convert- 
ing it  into  the  chloride  by  the  calculated  amount  of 
phosphorus  pentachloride,  putting  in  a  bulb  containing 
two  atoms  of  bromine  for  one  molecule  of  the  acid,  seal- 
ing the  tube,  breaking  the  bulb  containing  the  bromine 
by  shaking  the  tube,  and  heating,  till  vapors  of  bromine 
disappear,  in  a  water-bath.  On  cooling  and  opening 
the  tube  the  phosphorus  oxychloride  may  be  decom- 
posed by  shaking  with  cold  water  and,  in  case  the  chlo- 
ride of  the  acid  is  not  readily  decomposed  in  this  way, 
it  may  be  taken  up  with  ether,  the  solution  dried  with 
calcium  chloride,  the  ether  distilled,  and  the  chloride 
decomposed  by  warming  with  glacial  formic  acid.  See 
Baeyer  :  Ann.  Chem.  (L,iebig),  245,  175  ;  Aschan:  Ibid, 
271,  265. 

or-Brombutyric  acid  boils  with  some  decomposition  at 
2i2°-2i7°.  It  boils  without  decomposition  at  136°-! 38° 
under  a  pressure  of  35  mm.  The  specific  gravity  at  15° 
is  1.54.  It  dissolves  in  about  15  parts  of  water.  When 
treated  with  alcoholic  potash  it  is  converted  into  cis-cro- 

H  — C— C02H 
tonic  acid,  ||  .      The    yield    is,    however, 

H  — C  — CH3 

poor,  owing  to  the  formation  of  hydroxy-butyric  acid 
and  other  substances. 

33.  Preparation  of  a  Nitro  Derivative  of  an  Aromatic 

Acid.— Meta-nitro-benzoic  acid,  CflH4<^H  ^. 

Literature. — Mulder:  Ann.  Chem.  (lyiebig),  34,  297;  Gerland  : 
Ibid,  91,  186;  Griess:  Ber.  d.  chem.  Ges.,  8,  526;  10,  1871; 


96  ORGANIC   CHEMISTRY. 

Widmann :    Ann.   Chem.   (Liebig),    193,   202;    C.   I/iebermann ; 
Ber.  d.  chem.  Ges.,  10,  862  ;  Ernst :  Ztschr.  chem.,  1860,  477. 

25  grams  benzole  acid. 

50  grams  potassium  nitrate. 

75  grams  absolute  sulphuric  acid  (monohydrate). 

Warm  75  grams  of  absolute  sulphuric  acid1  to  70°  in  a 
beaker,  and  add,  in  small  portions,  a  powdered  mixture  of 
25  grams  of  benzoic  acid  and  50  grams  of  potassium 
nitrate,  stirring  vigorously  and  keeping  the  temperature 
at  8o°-9O°.  When  all  has  been  added,  and  the  nitro- 
benzoic  acid  has  separated  as  an  oily  layer  on  top,  pour 
the  contents  of  the  beaker  into  a  porcelain  dish,  and 
allow  the  product  to  solidify.  Separate  the  cake  of 
nitro  acids  from  the  acid  potassium  sulphate.  Put  in 
the  nitro  acids  (about  75  per  cent,  of  meta,  22  per  cent, 
of  the  ortho,  and  2^  per  cent,  of  the  para  acids  are  pres- 
ent in  the  mixture)  in  a  beaker  with  100  cc.  of  water, 
heat  till  the  acids  melt,  and  stir  thoroughly.  Cool,  filter, 
and  wash  with  cold  water.  Dissolve  the  acid,  in  300- 
400  cc.  of  hot  water,  and  add  a  clear  concentrated  solu- 
tion of  barium  hydroxide  (about  30  grams)  to  alkaline 
reaction.  Cool,  filter,  and  wash.  The  barium  salts  of 
the  ortho  and  para  acids  pass  into  the  filtrate,  while  a 
part  of  the  ortho  acid  remained  in  solution  on  treatment 
with  water  before.  The  pure  meta  acid  can  be  ob- 

1  Absolute  sulphuric  acid,  called  technically  the  "  monohydrate,"  can  be 
purchased  or  may  be  prepared  by  cooling  concentrated  sulphuric  acid  to  o°, 
or  below,  until  it  crystallizes  and  pouring  off  the  liquid  portion,  the  crystals 
consisting  of  absolute  sulphuric  acid,  if  the  acid  is  sufficiently  strong.  The 
crystallization  may  be  started  with  crystals  obtained  by  cooling  a  mixture  of 
ordinary  sulphuric  acid  with  the  fuming  acid. 


DKRIVATIVES   OF   ACIDS.  97 

tained  by  treating  the  barium  salt  with  200  cc.  of  hot 
water  and  some  hydrochloric  acid,  filtering  hot  from  the 
barium  sulphate,  which  separates,  and  cooling  the  fil- 
trate. 

Meta-nitro-benzoic  acid  melts  at  i4i°-i42°.  It  dis- 
solves in  10  parts  of  hot  water,  and  in  425  parts  of  water 
at  16.5°.  It  is  very  easily  soluble  in  alcohol  and  ether. 
The  barium  salt  is  soluble  in  19  parts  of  boiling  water, 
and  in  265  parts  of  cold  water. 

The  ortho  and  para  acids  may  also  be  separated  from 
the  mixture  obtained  by  the  nitration  of  benzoic  acid, 
but  are  more  readily  obtained  by  the  oxidation  of  the 
nitro-toluenes.  (See  5»  p.  24). 

34.  Preparation  of  an  Ammo  Acid  from  a  Halogen  De- 
rivative of  an  Acid.— Glycocoll,  CHt<Q<?fr  (Amino- 
ethanoic  acid.) 

Literature. — Braconiiot:  Ann.  Chim.  Phys.,  1820,  13,  114;  Per- 
kin,  Duppa:  Ann.  Chem.  (Liebig),  108,112;  Heintz :  Ibid,  122, 
257  ;  124,  297  ;  v.  Nencki  :  Ber.  d.  chem.  Ges.,  16,  2827  ;  Kraut ; 
Ann.  Chem.  (L,iebig),  266,  295  ;  Ber.  d.  chem.  Ges.,  23,  2577  ; 
Gabriel,  Kroseberg ;  Ibid,  22,  427. 

25  grams  monochloracetic  acid. 

25  cc.  water. 

300  cc.  ammonium  hydroxide  (sp.  gr.  0,90.). 

To  300  cc.  of  ammonia  (0.90)  in  a  liter  flask  or  dis- 
tilling bulb,  add  a  solution  of  25  grams  of  monochlor- 
acetic acid  in  25  cc.  of  water.  After  thorough  shaking, 
allow  the  whole  to  stand  for  24  hours.  Distil  off  most  of 
the  excess  of  ammonia  with  water  vapor  (see  i,  p.  14), 


98  ORGANIC   CHEMISTRY. 

and  evaporate  the  solution  on  the  water-bath  till  the 
odor  of  ammonia  is  no  longer  apparent.  Add  to  the 
solution  the  copper  oxide  prepared  from  35  grams  of 
copper  sulphate  by  precipitating  from  a  hot  solution 
with  sodium  hydroxide,  and  washing  twice  by  decanta- 
tion.  Boil,  filter,  evaporate,  and  crystallize  the  copper 
amino  acetate  which  is  formed. 

To  prepare  the  free  glycocoll,  dissolve  the  copper  salt 
in  water,  add  a  little  freshly  precipitated  and  slightly 
washed  aluminum  hydroxide,  precipitate  with  hydro- 
gen sulphide,  boil  a  few  minutes,  filter,  and  wash  with 
water  containing  a  little  hydrogen  sulphide.  Evaporate 
the  filtrate  to  a  small  volume  and  allow  the  glycocoll  to 
crystallize. 

In  case  the  glycocoll  contains  an  ammonium  com- 
pound, warm  the  concentrated  solution  with  milk  of 
lime  until  the  odor  of  ammonia  disappears,  filter,  pre- 
cipitate the  calcium  with  ammonium  carbonate,  filter, 
and  crystallize. 

The  addition  of  the  aluminum  hydroxide  prevents 
the  formation  of  a  colloidal  solution  of  the  copper  sul- 
phide which  is  difficult  to  filter. 

Yield  5  to  8  grams.  The  yield  is  very  con- 
siderably below  the  theoretical,  because  of  the  forma- 
tion of  the  secondary  and  tertiary  amino  acetic 
acid,  NH(CHaCO2H)a  and  N(CH,COiH)1.  The  large 
excess  of  ammonia,  and  the  quick  mixing  of  the  chlor- 
acetic  acid  with  the  ammonia,  after  it  has  been  added, 
tend  to  increase  the  amount  of  the  primary  compound 
which  is  desired. 


DERIVATIVES   OF   ACIDS.  99 

Glycocoll  crystallizes  in  monoclinic  crystals,  which 
turn  brown  at  228°,  and  melt  at  232°-236°.  It  is  soluble 
in  4.3  parts  of  cold  water,  in  930  parts  of  alcohol  of  0.828 
sp.  gr.,  and  insoluble  in  absolute  alcohol.  Its  neutral 
solution  gives  a  deep  red  color  with  ferric  chloride.  It 
forms  crystalline  salts  with  nitric  and  with  hydrochloric 
acid.  When  distilled  with  barium  hydroxide  it  gives 
methyl  amine  and  barium  carbonate.  With  nitrous  acid 

it  gives  glycollic  acid, 


35.  Preparation  of  an  Amino  Acid  from  the 
Half  Amide  of  a  Bibasic  Acid.  —  Anthranilic  acid, 

C6H4  <  ^|H     |^)    (2-Amino-benzoic  acid). 

Literature.  —  Laurent  :  Jsb.  d.  chem.,  1847-48,  589  ;  Ann. 
Chem.  (Liebig),  39,  91  ;  Kuhara:  Am.  Chem.  J.,  3,  29  ;  Aschan  ; 
Ber.  d.  chem.  Ges.,  19,  1402;  Fritzsche:  Ann.  Chem.  (Liebig), 
39,  83  ;  Beilstein,  Kuhlberg  :  Ibid,  163,  138  ;  Bedson  :  J.  Chem. 
Soc.,  37»  752,  (1880}  ;  Hoogewerf,  von  Dorp  ;  Rec.  trav.  chim.  d. 
Pays-Bas.,  10,  6  ;  Marignac:  Ann.  Chem.  (Liebig),  42,  215. 

20  grams  phthalic  anhydride. 

80  cc.  ammonia  (0.96). 

64  cc.  hydrochloric  acid  (1.112). 

16.5  grams  phthalamidic  acid. 

100  cc.  sodium  hydroxide,  (10  per  cent.). 

140  cc.  sodium  hydroxide  (10  per  cent.). 

1  6  grams  bromine  (5.1  cc.). 

35  cc.  hydrochloric  acid  (1.112). 

40  cc.  acetic  acid  (30  per  cent.). 

Put  20  grams  of  finely  powdered  phthalic  anhydride 


IOO  ORGANIC   CHEMISTRY. 

in  a  200  cc.  flask,  add  80  cc.  of  ammonia  of  sp.  gr.  0.96, 
shake  till  the  anhydride  dissolves,  which  should  take  only 
one  to  two  minutes.  Cool  at  once,  filter,  if  any  crystals 
of  the  anhydride  remain,  to  the  filtrate  add  64  cc.  of  hy- 
drochloric acid  (4  cc.  =  i  gram) ,  cool  again  thoroughly 
with  shaking,  filter  off  on  a  plate,  stop  the  pump, 
moisten  with  water,  suck  off  and  repeat  once.  Dry  the 

CO  TT 
phthalamidic  acid,  ^6H4<QQNH  '  on  filter  PaPer  in  the 

air,  or,  better,  in  vacua  over  sulphuric  acid.  It  should 
show  nearly  or  quite  the  proper  melting-point  of  148°- 
149°,  and  the  yield  should  be  about  20  grams. 

Put  140  cc.  of  a  ten  per  cent,  solution  of  sodium  hy- 
droxide in  a  flask,  add  from  a  burette  16  grams  (5.1  cc. 
=  i  mol.)  of  bromine,  and  dissolve  it  immediately  by 
giving  the  flask  a  quick  rotary  motion.  Dissolve  16.5 
grams  (i  mol.)  of  phthalamidic  acid  in  100  cc.  of  ten 
per  cent,  sodium  hydroxide,  and  add  the  solution  of 
sodium  hypobromite  in  portions  of  about  20  cc.  at  in- 
tervals of  one  to  two  minutes,  cooling  after  each  addi- 
tion. Neither  solution  should  stand  but  a  few  minutes 
before  use.  Allow  the  mixture  to  stand  for  half  an 
hour,  add  a  little  of  a  strong  solution  of  acid  sodium  sul- 
phite to  reduce  the  excess  of  sodium  hypobromite,  and 
35  cc.  of  hydrochloric  acid  (4  cc.  =  i  gram),  carefully, 
on  account  of  the  effervescence.  Evaporate  to  about  100 
cc.  Filter,  if  necessary,  and  add  40  cc.  of  acetic  acid 
(30  per  cent. ) .  Filter  off  the  anthranilic  acid;  after  cool- 
ing, suck  it  as  free  as  possible  of  the  mother- liquors  and 
recrystallize  from  hot  water.  Yield  10  to  1 1  grams. 


DERIVATIVES   OF   ACIDS.  IOI 

For  a  discussion  of  the  reactions  involved  in  the  trans- 
formation of  the  amide  group  into  an  amino  group  with 
loss  of  carbonyl  see  Chapter  V. 

Anthranilic  acid  crystallizes  in  leaflets  which  melt  at 
I44°-I45°.  It  is  easily  soluble  in  water.  The  aqueous 
solution  shows  a  blue  fluorescence  and  tastes  sweet. 

The  preparation  of  anthranilic  acid  from  indigo  is  of 
especial  historic  interest.  The  acid  may  also  be  pre- 
pared by  the  reduction  of  orthonitrobenzoic  acid. 

36.  Preparation  of  a  Hydroxy  Acid  by  Treatment  of 
the  Sodium  Salt  of  a  Phenol  with  Carbon  Dioxide 

(Kolbe's  Synthesis).— Salicylic  acid,  C6H4<^H   fy 
(0-Oxybenzoic  acid). 

Literature. — Gerhard t :  Ann.  Chem.  (Liebig),  45,  21  ;  Kohler: 
Ber.  d.  chem.  Ges.,  12,  246 ;  Earth  :  Ann.  Chem.  (I/iebig),  154, 
360  ;  Hiibner :  Ibid,  162,  71  ;  Gerland  :  Ibid,  86,  147  ;  Kolbe, 
L,anteman  :  Ibid,  115,  201  ;  Kolbe  :  J.  prakt.  Chem.,  [2],  10,  93; 
Hentschel :  Ibid,  [2],  27,  41 ;  Schmitt :  Ibid,  [2],  31,  407;  Reimer, 
Tiemann  :  Ber.  d.  chem.  Ges.,  9,  423,  824;  10,  63,  213. 

12.5  grams  sodium  hydroxide. 

30  grams  phenol. 

20  cc.  water. 

Dissolve  12.5  grams  of  sodium  hydroxide  in  20  cc.  of 
water  in  a  porcelain,  or  better  in  a  nickel  dish.  Add, 
in  portions,  30  grams  of  crystallized  phenol.  Fasten  the 
dish  firmly  by  means  of  a  clamp  and,  with  the  burner  in 
the  hand  and  in  constant  motion,  heat  and  stir  carefully 
till  a  thoroughly  dry  powder  is  obtained.  Transfer  this 
at  once  to  a  TOO  cc.  distilling  bulb,  or  retort,  place  the 


102  ORGANIC   CHEMISTRY. 

latter  in  an  oil-  bath  and  pass  through  it  a  current  of 
dry  hydrogen,  while  the  bath  is  heated  to  140°  for  hall 
an  hour. 

The  salt  should  be  so  dry  that  it  does  not  sinter  to- 
gether during  this  part  of  the  process.  Allow  the  oil- 
bath  to  cool  to  110°,  and  pass  a  current  of  dry  carbon 
dioxide  through  the  bulb  for  one  hour.  Then  allow  the 
temperature  to  rise  at  the  rate  of  about  20°  an  hour  till 
a  temperature  of  200°  is  reached,  and  heat  finally  for  an 
hour  at  that  temperature,  continuing  a  slow  current  of 
carbon  dioxide.  The  side  tube  of  the  distilling  bulb 
should  be  heated  gently,  once  in  a  while,  to  melt  the 
phenol  which  distils  over.  Cool,  rinse  the  phenol  out  of 
the  side  tube,  dissolve  the  residue  in  the  distilling  bulb 
in  water,  filter,  if  necessary,  and  precipitate  the  salicylic 
acid  from  the  filtrate  with  concentrated  hydrochloric 
acid.  Recrystallize  from  water,  using  a  little  bone- 
black  if  the  acid  is  colored. 

The  carbon  dioxide  combines  with  the  sodium  pheno- 

f~\  _  S-\     TT 

late  to  form  a  phenyl  sodium  carbonate,  CO^-    6     5* 


This,  at  a  higher  temperature,  rearranges  itself  to  form 
the  sodium  salt  of  salicylic  acid.  The  latter  reacts  with 
another  molecule  of  the  phenolate  liberating  phenol. 

ONa 


.  , 

C6H4(  +  C6H6ONa  =  C6H4(  + 

XC02Na  XCO2Na 

C6H6OH. 

By  heating  with  carbon  dioxide  under  pressure  at  140° 
this  second  reaction  can  be  avoided,  and  all  of  the  pheno- 


K* 


DERIVATIVES   OF  ACIDS.  103 

late  converted  into  the  salicylate.     Yield  5  to  10  grams. 

The  potassium  phenolate  reacts  at  150°  in  the  same 
manner  as  the  sodium  salt,  but  at  220°  it  gives  the  para- 
hydroxybenzoate  instead  of  the  salicylate. 

This  synthesis  is  quite  general  in  its  application,  and 
derivatives  of  phenol  react  in  a  manner  similar  to  phenol 
itself. 

Salicylic  acid  crystallizes  in  white  needles  which  melt 
at  156°.  The  solution  gives  an  intense  violet  color  with 
ferric  chloride,  a  reaction  characteristic  of  all  orthohy- 
droxy  acids  of  the  benzene  series.  Salicylic  acid  is 
often  used  in  articles  of  food  on  account  of  its  antiseptic 
properties,  and  the  reaction  with  ferric  chloride  is  made 
use  of  in  its  detection. 

37.  Reduction  of  an  Unsaturated  Acid  by  Sodium 
Amalgam. — Hydrocinnamic  acid,  C6H6CH2CH2CO2H, 
(Phen-3-propanoic  acid.) 

Literature. — (See  13,  p.  55.) 

10  grams  cinnamic  acid. 

60  cc.  water. 

27  cc.  sodium  hydroxide  (10  per  cent.). 

135  grams  sodium  amalgam  (3  per  cent.). 

Put  in  a  200  cc.  wide-mouthed  bottle  10  grams  of  cin- 
namic acid,  60  cc.  of  water,  27  cc.  sodium  hydroxide  (10 
percent.),  and  135  grams  of  sodium  amalgam  (3  per 
cent.) .'  Shake  for  some  time,  till  the  amalgam  becomes 

1  Weigh  out  in  a  dry  mortar  130  grains  of  pure  mercury  (amalgam  from 
impure  mercury  is  much  less  effective ;  Aschan :  Ber.  d.  chem.  Ges.,  24, 
1865  ;  E.  Fischer;  Ibid,  25,  1255).  Clean  4  grams  of  sodium,  cutoff  a  thin  slice 
and  press  it  to  the  bottom  of  the  mortar  with  the  pestle,  and  press  gently  till 


104  ORGANIC    CHEMISTRY. 

liquid.  Take  out  a  few  drops  of  the  solution,  dilute, 
pass  carbon  dioxide  through  it  and  add  a  drop  of 
a  dilute  solution  of  potassium  permanganate.  If  the 
permanganate  is  decolorized  or  turns  brown  at  once, 
cinnamic  acid  is  still  present  and  the  solution  must  be 
warmed  in  a  water-bath,  shaken  occasionally,  and,  if 
necessary,  more  amalgam  added  till  the  solution  no 
longer  decolorizes  permanganate.  This  permanganate 
test  has  proved  of  great  value  for  the  detection  of  un- 
saturated  bodies  in  many  similar  cases.  The  test  can- 
not be  applied  to  the  alkaline  solution  without  passing 
carbon  dioxide  through  it,  because  it  is  masked  by  the 
formation  of  a  green  manganate. 

When  the  reduction  is  complete,  pour  off  from  the 
mercury  and  precipitate  the  hydrocinnamic  acid  by  add^ 
ing  22  to  25  cc.  of  concentrated  hydrochloric  acid.  The 
acid  usually  separates  as  an  oil  which  solidifies  on  al- 
lowing the  cold  solution  to  stand.  Filter  off,  and  recrys- 
tallize  from  hot  water.  Yield  9  grams. 

Hydrocinnamic  acid  crystallizes  in  long  colorless 
needles  which  melt  at  49°.  It  boils  at  280°.  It  is  easily 
soluble  in  boiling  water,  in  alcohol,  and  in  ether.  It  is 
volatile  with  water  vapor,  and  solutions  of  it  cannot  be 
concentrated  by  boiling  without  loss.  It  is  soluble  in 
1 68  parts  of  water  at  20°. 

the  somewhat  violent  reaction  takes  place.  Add  a  second  piece  in  the  same 
way  and  continue  as  rapidly  as  possible  till  all  is  added.  If  the  operation  is 
conducted  quickly,  all  can  be  added  before  the  mass  solidifies.  Break  up 
the  amalgam  at  once  and  transfer  it  to  a  tightly  stoppered  bottle. 


CHAF»TBR  III. 


Halogen  Compounds* 

Chlorine  and  bromine  derivatives  of  the  hydrocarbons 
may  be  obtained  by  the  direct  action  of  the  elements  on 
the  hydrocarbons.  In  the  fatty  acid  series  of  hydrocar- 
bons this  method  of  preparation  is  of  scarcely  more  than 
theoretical  interest,  partly  because  the  hydrocarbons  are 
difficult  to  obtain  in  pure  condition,  and  partly  because 
both  primary  and  secondary  halogen  alkyls  are  formed, 
and  frequently  di-  and  tri-substitution  products  as  well. 
If  a  complete  replacement  of  the  hydrogen  by  chlorine 
or  bromine  is  desired,  the  addition  of  a  small  amount  of 
iodine  greatly  facilitates  the  action.  (For  the  chlorina- 
tion  of  butane  from  petroleum,  see  Mabery:  Am.  Chem. 
J.,  19,  247.) 

In  the  aromatic  series  direct  replacement  of  hydrogen 
by  chlorine  or  bromine  takes  place  easily,  and  pure  prod- 
ucts are  readily  obtained.  In  this  series,  also,  the  pres- 
ence of  some  substances  greatly  facilitates  the  reaction, 
the  bodies  most  frequently  used  for  the  purpose  being 
ferric  chloride  or  bromide. 

The  action  of  chlorine  or  bromine  on  aromatic  hydro- 
carbons in  the  cold  and  dark,  but  with  the  addition  of 
ferric  chloride  or  bromide,  (or  some  powdered  iron), 
causes  a  substitution  of  the  hydrogen  in  the  nucleus, 
and  usually  in  the  para  or  ortho  position  with  reference 
to  the  side  chain.  In  the  sunlight,  or  with  the  boiling 


106  ORGANIC   CHEMISTRY. 

hydrocarbon,  the  substitution  takes  place  in  the  side 
chain.  (Beilstein  and  Geitner  :  Ann.  Chem.  (Liebig), 
J39»  33i  ;  Jackson  :  Am.  Chem.  J.,  i,  94;  2,  i.) 

The  monohalogen  derivatives  of  saturated  hydrocar- 
bons are  usually  most  easily  obtained  from  the  corres- 
ponding alcohols  by  treatment  with  phosphorus  trichlo- 
ride, tribromide  (or  red  phosphorus  and  bromine),  or 
pentaiodide, 

3ROH  +  PBr,  =  3RBr  +  H9POS. 
5ROH  +  5I  +  P  =  5RI  +  H3P04  +  H,0. 

Di-halogen  substitution  products  are  often  obtained 
from  hydrocarbons  of  the  ethylene  series  by  direct  addi- 
tion, giving  compounds  in  which  the  halogen  atoms  are 
combined  with  adjacent  carbon  atoms.  They  may  also 
be  obtained  from  ketones  or  aldehydes  by  treatment 
with  phosphorus  pentachloride  or  pentabromide,  giving 
compounds  in  which  the  halogen  atoms  are  combined 
with  the  same  carbon  atom. 

R\  R\ 

;CO  +  PC16  i=       )CC12  +  POC13. 

RX  R/ 

Monohalogeu  derivatives  of  the  ethylene  series  may  be 
prepared  by  treating  di-halogen  derivatives  of  the  marsh 
gas  series  with  alcoholic  potash  or  soda. 

CnHanBra  +  KOH  —  CJI^Br  +  KBr  +  HaO. 

In  the  aromatic  series  halogen  derivatives  are  often 
prepared  from  amines  by  passing  through  the  diazo 
compounds  (Sandmeyer's  reaction). 


HALOGEN    COMPOUNDS.  IOy 

RNH2HC1  +  HNOa  =  RN=N  +  2HfO. 

Cl 
RN=N  +  Cu3Cla  =  RC1  +  Na  +  CuaCla. 

Cl 

Finely  divided  metallic  copper  may  be  used  in  place 
of  the  cuprous  chloride  (Gattermann's  reaction). 

For  iodine  derivatives  a  very  clean  reaction  can  often 
be  obtained  by  mixing  such  an  acid  diazo  solution  as 
is  described  on  pp.  43  and  115,  or  one  containing  some- 
what more  acid,  with  an  excess  of  potassium  iodide  and 
warming  the  solution. 

The  action  of  hypochlorites,  hypobromites,  or  hypo- 
iodites  upon  some  organic  compounds  causes  a  substitu- 
tion of  halogen  atoms  for  hydrogen,  a  reaction  which  is 
of  very  great  technical  importance  in  the  preparation  of 
chloroform  and  iodoform.  In  the  former  case,  when 
acetone  is  used,  three  hydrogen  atoms  in  one  of  the 
methyl  groups  appear  to  be  at  first  replaced  by  chlorine. 

2CH3— CO— CH3  +  3CaOaCla  =  2CC18COCH3  + 

3Ca(OH)a. 

The  accumulation  of  negative  atoms  appears  to  ren- 
der the  trichloracetone  unstable  toward  bases,  and  it  de- 
composes in  a  manner  which  recalls  the  ' '  acid  decom- 
position" of  /?-ketonic  acids  (see  p.  9). 

2CC13COCH8  +  Ca(OH),  =   2CHC1,  +  Ca(CH3COa)a. 
Most  of  the  methods  given  for  the  preparation  of  halo- 
gen derivatives  of  hydrocarbons  may  also  be  used  for 


io8 


ORGANIC   CHEMISTRY. 


the  preparation  of  the  halogen  derivatives  of  other  car- 
bon compounds. 

38.  Preparation  of  an  Iodine  Derivative  of  a  Hydro- 
carbon from  an  Alcohol. — Methyl  iodide,  CH8I. 

Literature.— Dumas,  Peligot :  Ann.  Chem.  (Liebig),  13,  78 ; 
Rieth,  Beilstein  ;  Ibid,  126,  250  ;  Walker  ;  J.  Chem.  Sqc.,  61,  717. 

10  grams  red  phosphorus. 

35  grams  methyl  alcohol. 

loo  grams  iodine. 

Place  in  a  100  cc.  distilling  bulb  10  grams  of  red  phos- 


Fig.  18. 

phorus,  add  35  grams  (43  cc.)  of  methyl  alcohol,  and 
then,  in  small  portions,  and  with  careful  cooling  100 
grams  of  iodine.  Allow  the  mixture  to  stand  in  cold 
water  for  an  hour  and  then  distil  from  the  water-bath, 
using  a  good  condenser.  Shake  the  distillate  twice  with 
an  equal  volume  of  water,  separating  with  a  separatory 


HALOGEN    COMPOUNDS.  ICQ 

funnel  (see  5>  p.  25),  add  once  more  an  equal  volume  of 
water  and,  with  frequent  shaking,  caustic  soda  till  the 
methyl  iodide  is  colorless.  Separate  again,  transferring 
the  iodide  to  a  small  distilling  bulb,  add  some  fused, 
powdered  calcium  chloride  and  distil  again  from  the 
water-bath  after  about  an  hour,  using  a  thermometer. 

Methyl  iodide  boils  at  42.8°,  and  has  a  specific  gravity 
of  2.2852  at  15°,  or  2.2529  at  25°.  On  heating  with  fif- 
teen parts  of  water  at  100°  it  is  converted  into  methyl 
alcohol  and  hydriodic  acid. 

Because  of  its  low  boiling-point  and  high  molecular 
weight  it  escapes  rapidly  unless  kept  in  small  bottles 
tightly  stoppered  with  cork  stoppers,  or,  better,  in  sealed 
tubes.  For  the  preparation  of  large  quantities  of  ethyl 
or  methyl  iodide  the  method  of  Walker  (loc.  cit.)  is  to 
be  recommended. 

38.  Preparation  of  a  Bromine  Derivative  of  a  Hy- 
drocarbon from  an  Alcohol  with  Sulphuric  Acid  and 
Potassium  Bromide.— Ethyl  bromide,  CaH6Br. 

Literature  — Serullas  :  Ann.  Chim.  Phys.  [2],  34,  99,  (1827); 
Loewig  :  Ann.  Chem.  (Liebig),  3,  288  ;  Perkin  :  J.  prakt.  Chem., 
31,  497  ;  R.  Schiff :  Ber.  d.  chem.  Ges.,  19,  563  ;  Riedel :  Ibid,  24, 
R.  105. 

90  grams  potassium  bromide. 
100  cc.  alcohol. 

100  cc.  concentrated  sulphuric  acid. 
70  cc.  water. 

Put  zoo  cc.  of  concentrated  sulphuric  acid  in  a  flask, 
add  slowly  with  constant  shaking,  but  within  two  or 
three  minutes,  100  cc.  of  alcohol.  Cool  thoroughly  and 


IIO  ORGANIC   CHEMISTRY. 

pour  the  mixture  into  a  400  cc.  distilling  bulb  or  flask 
containing  70  grams  of  potassium  bromide,  and  70  cc.  of 
water.  Distil  quite  rapidly,  heating  on  a  wire  gauze 
covered  with  a  thin  sheet  of  asbestos  and  using  a  good 
condenser,  as  long  as  ethyl  bromide  comes  over.  A 
little  water  should  be  placed  in  the  receiver  to  absorb 
hydrobromic  acid  which  is  given  off.  Separate  the 
ethyl  bromide  from  the  aqueous  layer  and  add  to  it,  with 
careful  cooling,  concentrated  sulphuric  acid  till  the  acid 
separates  below.  This  will  remove  any  ether  which  has 
been  formed.  Separate  again,  wash  twice  with  a  small 
amount  of  water,  put  the  bromide  in  a  distilling  bulb 
with  some  fused,  powered  calcium  chloride  and  distil 
with  a  thermometer  after  one  or  two  hours.  Yield  55  to 
60  grams. 

The  reactions  involved  in  the  preparation  are  as  fol- 
lows : 

CaH6OH  +  H2S04  =  C3HBHS04  +  H3O. 
Ethyl  sulphuric  acid. 

CaH5HS04+  KBr=  CaH5KSO4  +  HBr. 

Ethyl  potassium  sulphate. 

C3H5KSO4  +  HBr  =  C2HBBr  +  HKSO4. 
Ethyl  bromide  may  also  be  prepared  by  the  action  of 
bromine  on  red  phosphorus  and  alcohol,  but  the  method 
here  given  is  more  satisfactory  and  gives  a  purer  prod- 
uct, unless  red  phosphorus  free  from  arsenic  is  available. 
Ethyl  bromide  boils  at  38.4°,  and  has  a  specific  gravity 
of  1.476  at  15°.     It  must  be  kept  in  tightly  corked,  not 
glass  stoppered  bottles. 

Ethyl  bromide  is  sometimes  used  as  an   anaesthetic. 


HALOGEN   COMPOUNDS.  Ill 

For  this  use  it  must  be  entirely  free  from  arsenic. 
Arsenic,  if  present,  may  be  detected  by  burning  the  sub- 
stance in  a  small  spirit  lamp,  and  drawing  the  products 
of  combustion  through  a  solution  of  caustic  soda.  The 
solution  may  then  be  tested  for  arsenic  by  means  of  hy- 
drochloric acid  and  a  concentrated  solution  of  stannous 
chloride. 

40.  Preparation  of  a  Bromine  Derivative  of 
an  Aromatic  Hydrocarbon. —  Para-dibrombenzene, 

OTT      Br  (i) 

C'-^Br  (4)' 

Literature. — Couper  :  Ann.  Chim.  Phys.  [3],  52,  309,  (1858); 
Riese  ;  Ann.  Chem.  (Liebig),  164,  162  ;  Jannasch;  Ber.  d.  chem. 
Ges.,  10,  1355. 

50  grams  benzene  (56.5  cc.). 

210  grams  bromine  (67  cc.). 

i  gram  iron  filings. 

Put  50  grams  of  benzene  in  a  dry,  200  cc.  flask.  Add 
i  gram  of  iron  filings  or  turnings,  and  close  the  mouth 
with  a  stopper  bearing  a  drop  funnel  which  dips  below 
the  surface  of  the  benzene,  and  an  exit  tube.  Putin  the 
drop  funnel,  best  out  of  doors,  67  cc.  of  bromine.  Place 
the  flask  in  a  water-bath  filled  with  cold  water,  and  con- 
nect the  exit  tube  with  a  tube  opening  just  above  the 
surface  of  water  in  a  large  bottle.  Allow  the  bromine 
to  flow  slowly  into  the  benzene.  Toward  the  end,  aid 
the  reaction  by  heating  the  water-bath  slowly  to  the 
boiling-point. 

When  the  reaction  is  complete  and  no  more  vapors  of 
bromine  appear,  distil  from  the  flask  or  from  a  distilling 


112  ORGANIC    CHEMISTRY. 

bulb,  collecting  the  portion  boiling  at  2oo°-23o°  by  itself. 
Crystallize  from  a  small  amount  of  alcohol.  Yield  50  to 
60  grams  of />-dibrombenzene. 

Para-dibrombenzene  crystallizes  in  white  prisms  or 
leaflets  which  melt  at  89°,  and  boil  at  219°. 

41.  Substitution  of  Chlorine  in  the  Side  Chain  of  an 
Aromatic  Hydrocarbon. — Benzyl  chloride,  C6HBCH2C1. 

Literature. — Cannizzaro  :  Ann.  Chem.  (Liebig),  96,  246  ;  Beil- 
stein,  Geitner  :  Ibid,  139*332;  Ivauth,  Grimaux  :  Ibid,  143,  80; 
Schramm  ;  Ber.  d.  chem.  Ges.,  18,608;  Haase  :  Ibid,  26,  1053. 

100  grams  toluene. 

loo  grams  manganese  dioxide. 

540  cc.  commercial  hydrochloric  acid. 

Put  in  a  200  cc.  flask  100  grams  (115  cc.)  of  toluene 
and  connect  it  with  an  upright  condenser.  Place  in  the 
upper  end  of  the  condenser  a  tight  stopper  bearing  two 
glass  tubes,  one  passing  just  through  the  stopper  and  the 
other  reaching  nearly  to  the  bottom  of  the  flask.  Con- 
nect the  first  tube  with  a  tube  opening  just  above  the 
surface  of  water  in  a  bottle.  Or  arrange  one  tube  pass- 
ing through  the  stopper  side  of  the  condenser,  and  con- 
nect the  other  with  the  top  of  the  condenser,  as  in  Fig. 
19.  Heat  the  toluene  to  boiling  and  pass  in  chlorine 
generated  in  a  liter  flask  by  the  slow  addition  of  540  cc. 
of  commercial  hydrochloric  acid  to  100  grams  of  manga- 
nese dioxide,  the  mixture  being  warmed  gently  and  the 
gas  purified  by  passing  it  through  a  wash-bottle  con- 
taining water,  and  then  through  one  containing  concen- 
trated sulphuric  acid.  The  operation  must  be  carried 
out  in  clear  daylight,  or,  if  possible,  in  the  direct  sunlight. 


HALOGEN   COMPOUNDS. 


Fig.  19. 

When  the  evolution  of  chlorine  has  ceased,  submit  ther* 
product  in  the  flask  to  fractional  distillation.  The  por- 
tion boiling  below  150°  consists  chiefly  of  unchanged 
toluene  and  may  be  used  for  a  new  preparation.  After 
fractioning  two  or  three  times  the  portion  boiling  at 
i76°-i8i°  will  consist  of  nearly  pure  benzyl  chloride. 
The  yield  varies  according  to  the  brightness  of  the  sun- 
light in  which  the  operation  is  conducted.  In  some 
cases  the  weight  of  benzyl  chloride  may  equal  that  of 
the  toluene  used. 

Benzyl  chloride  is  a  colorless  liquid  with  an  unpleas- 
ant odor.     Its  vapor  attacks  the  eyes  very  strongly.     It 


114  ORGANIC   CHKMISTRY. 

boils  at  178°  and  has  a  specific  gravity  of  1.113  at  J5°- 
By  long  boiling  with  water  it  is  converted  into  benzyl 
alcohol.  Oxidizing  agents  oxidize  it  to  benzoic  acid.. 
The  higher  boiling  portions  contain  some  benzal  chlo- 
ride, C6H6CHC12,  which  boils  at  203.5°. 

42.  Preparation  of  a  Bromine  Derivative  of  a  Hydro- 
carbon from  an  Aromatic  Amine. — Parabromtoluene, 

CH3(i). 
C«H«<Br      (4). 

Literature. -Hiibner,  Wallach :  Ann.  Chem.  (Liebig),  154* 
293;  Glinzer,  Fittig;  Ibid,  136,301;  Michaelis,  Genzken  :  Ibid, 
242,  165 ;  Ladenburg  :  Ber.  d.  chem.  Ges.,  7,  1685  ;  Sandmeyer  : 
Ibid,  17,2652;  Schramm;  Ibid,  18,606;  Gasiorowski  u.  Wayss; 
Ibid,  18,  1936;  Gattermann ;  Ibid,  23,  1218;  Erdmann:  Ann. 
Chem.  (Liebig),  272,  141. 

25  grams  copper  sulphate. 
72  grams  potassium  bromide. 

9  grams  (5  cc.)  sulphuric  acid  (1.84). 

10  grams  reduced  copper. 
1 60  grams  water. 

21.4  grams  para-toluidine. 

80  cc.  water. 

29  grams  sulphuric  acid  (15.7  cc.). 

loo  grams  ice. 

14  grams  sodium  nitrite. 
70  cc.  water. 

In  a  liter  flask  put  25  grams  (i  mol.)  of  crystallized 
copper  sulphate,  72  grams  (6  mols.)  of  potassium  bro- 
mide, TOO  cc.  of  water,  10  grams  of  reduced  copper  or 


HAI.OGKN    COMPOUNDS.  115 

copper  turnings,  and  9  grams  (5  cc.,  i  mol.)  of  concen- 
trated sulphuric  acid.  Heat  on  asbestos  with  an  upright 
•condenser  to  gentle  boiling  till  the  solution  is  colorless. 

Meanwhile  put  in  a  beaker  21.4  grams  (2  mols.)  of 
paratoluidine,  add  80  cc.  of  water  and  29  grams  (15.7 
cc.,  3  mols.)  of  concentrated  sulphuric  acid.  The  tolu- 
idine  should  dissolve  in  hot  solution  to  insure  its  com- 
plete conversion  into  the  sulphate.  Stir  and  cool  till  the 
sulphate  has  separated  in  finely  divided  condition. 
Add  100  grams  of  ice  and,  when  the  temperature  has 
fallen  to  o°,  add  slowly,  with  stirring,  14  grams  (2 
mols.)  of  sodium  nitrite  dissolved  in  70  cc.  of  water. 
After  standing  for  five  minutes  the  solution  should  react 
for  nitrous  acid  when  a  drop  is  placed  on  starch  iodide 
paper.  If  it  does  not,  a  little  more  of  the  nitrite  must 
be  added,  but  the  least  possible  excess  must  be  used. 
Neither  the  diazo  solution,  nor  that  of  the  cuprous  bro- 
mide should  be  allowed  to  stand  long  after  they  are  pre- 
pared, because  of  the  tendency  of  the  former  to  decom- 
pose, and  of  the  latter  to  oxidize. 

Cool  the  cuprous  bromide  solution  very  slightly,  and 
add  the  diazo  solution  slowly,  shaking  vigorously  and 
warming  the  solution  on  a  vigorously  boiling  water- 
bath.  The  whole  of  the  solution  should  be  added  within 
2  to  3  minutes,  if  possible  without  cooling  it  too  far. 
The  diazo  solution  is  best  added  through  a  funnel  with 
a  long  stem. 

It  is  impossible  in  any  case,  apparently,  to  secure  a 
perfectly  clean  reaction.  Three  different  reactions  may 
take  place: 


Il6  ORGANIC   CHEMISTRY. 

C7H7N=N  +  H9O  =  C7H7OH  +  Na  +  HBr. 

Br 
2C7H7N=N+CuaBra  =  C7H7N=NC7H7+Na+2CuBra. 

Br 
C,H7N=N  +  CuaBra  =  C7H7Br  +  Ns  +  CuaBra. 

Br 

The  first  reaction  takes  place  if  the  diazo  solution  de- 
composes before  it  is  added  to  the  cuprous  bromide,  or  if 
it  is  added  to  the  hot  solution  in  such  a  manner  that  it 
is  not  immediately  mixed  with  it,  so  that  the  diazo  com- 
pound has  an  opportunity  to  combine  with  the  cuprous 
bromide.  Hence  the  necessity  of  vigorous  shaking  to 
secure  a  rapid  and  thorough  mixture  of  the  solutions. 
The  second  reaction  is  apparently  favored  when  the 
diazo-cuprous  bromide  remains  in  the  cool  solution  un- 
decomposed.  The  best  conditions  for  the  reaction  ap- 
pear to  be  secured  at  the  lowest  temperature  of  rapid  de- 
composition for  the  diazo-cuprous  compound.  This  tem- 
perature varies  in  different  cases.  It  is  much  higher  for 
paradiazotoluidine  then  for  the  ortho  compound,  appar- 
ently because  of  the  greater  stability  of  the  former.  ( See 
Krdmann  :  loc.  tit. ) 

When  the  diazo  solution  has  all  been  added,  distil 
over  the  parabromtoluene  in  a  rapid  current  of  water 
vapor  (seei, p.  14),  shake  it  with  some  sodium  hydroxide 
solution  to  remove  any  paracresol  present,  separate  it 
from  the  solution,  dry  by  allowing  it  to  stand  for  some 


HALOGEN    COMPOUNDS.  1 17 

time  with  solid  caustic  potash,  pour  off  or  filter  through 
a  dry  filter,  and  distil  from  a  small  distilling  bulb,  using 
a  condensing  tube  or  distilling  slowly  into  a  bottle  or 
tube.  Yield  about  20  grams. 

Parabromtoluene  crystallizes  in  rhombic  plates,  which 
melt  at  28.5°.     It  boils  at  185.2°,   and  has  a   specific 

gravity  of  1.3897  at  —5-.     Oxidizing  agents  convert  it 
4 

into  parabrombenzoic  acid. 

43.  Preparation  of  a  Dibrom-derivative  of  a  Satura- 
ted Hydrocarbon  from  a  Hydrocarbon  of  the  Ethylene 

CH9Br 

Series.— Ethylene  bromide,  |         (dibrom  (1.2)  ethane). 

CHaBr 

Literature.— Balard :  Ann.  Chim.  Phys.  [2],  32,  375(1826); 
Erlenmeyer  and  Bunte  ;  Ann.  Chem.  (Liebig),  168,  64  ;  Denzel: 
Ibid,  195,  210;  Thorpe:  J.  Chem.  Soc.,  37, 177  (1880)  ;  Anschiitz: 
Ann.  Chem.  (Iviebig),  221,  137  ;  V.  Meyer  u.  Miiller  :  Ber.  d. 
chem.  Ges.,  24,4249;  Tawildarow :  Ann.  Chem.  (lyiebig),  176, 
12. 

30  cc.  alcohol. 

50  cc.  sulphuric  acid  (1.84). 

loo  cc.  alcohol. 

loo  cc.  sulphuric  acid. 

40  cc.  (120  grams)  bromine. 

Put  30  cc.  of  alcohol  in  a  liter  flask.  Add  50  cc.  con- 
centrated sulphuric  acid.  Connect,  as  shown  in  the 
figure,  with  a  wash-bottle  containing  caustic  soda,  and 
with  a  second  wash-bottle  containing  concentrated  sul- 
phuric acid  and  having  a  safety-tube,  then  with  a  glass- 


Il8  ORGANIC   CHEMISTRY, 

stoppered  wash-bottle  containing  40  cc.  of  bromine  cov- 
ered with  a  little  water.  The  latter  should  be  placed  in 
cold  water  and  connected  with  a  tube  opening  just  above 
the  surface  of  a  sodium  hydroxide  solution  in  a  large  bot- 
tle. Place  the  generating  flask  on  a  thin  asbestos  paper, 
and  heat  till  the  thermometer  (not  shown  in  the  figure)  in 
the  mixture  reaches  I7o°-i75°.  When  the  evolution  of 
ethylene  has  well  begun,  drop  in  slowly  a  mixture  of  100 


cc.  of  alcohol  with  icocc.  of  concentrated  sulphuric  acid, 
keeping  the  temperature  at  about  170°.  Continue  the  pas- 
sage of  the  gas  till  the  bromine  becomes  nearly  colorless. 
The  mixture  in  the  generating  flask  should  not  carbonize. 
If  it  should  do  so  from  too  rapid  heating,  it  is  usually 
best  to  empty  the  flask  and  put  in  a  new  mixture  of 
alcohol  and  acid.  Transfer  the  ethylene  bromide  to  a 
separatory  funnel,  add  some  water  and  agitate  gently 


HAIvOGEN   COMPOUNDS.  119 

(see  5»  p.  25),  separate,  add  a  dilute  solution  of  sodium 
hydroxide  to  alkaline  reaction,  shaking  gently  with 
care  not  to  form  an  emulsion,  separate  again,  dry  by 
allowing  to  stand  for  several  hours  with  fused  calcium 
chloride,  filter  into  a  dry  distilling  bulb,  and  distil. 
Yield  nearly  equal  to  the  weight  of  the  bromine  used. 

Ethylene  bromide  solidifies  at  a  low  temperature  and 
melts  at  9.5°.  It  boils  at  131.5°,  and  has  a  specific 
gravity  of  2.1785  at  20°.  When  warmed  in  alcoholic 
solution  with  granulated  zinc,  ethylene  is  regenerated. 
With  alcoholic  potash  vinyl  bromide  and  acetylene  are 
formed. 

44.  Preparation  of  a  Chlorine  Derivative  of  a  Hydro- 
carbon by  the  Use  of  Calcium  Hypochlorite. — Chloro- 
form, CHC13,  trichlormethane. 

Literature — Soubeiran  :  Ann.  Chim.  Phys.  [2],  48,  131  (1831) ; 
Liebig:  Ann.  Chem.  (Liebig),  i,  199;  Belohoubek :  Ibid,  165, 
349;  Goldberg:  J.  prakt.  Chem.  [2],  24,  109  (1881);  Bechamp: 
Ann.  Chim.  Phys.  [5],  22,  347  (1881)  ;  Orndorff  and  Jessel :  Am. 
Chem.  J.,  10,  365 ;  E.  R.  Squibb ;  J.  Am.  Chem.  Soc.,  18,  231. 

150  grams  bleaching  powder. 

450  cc.  H2O. 

12  grams  (16  cc.)  acetone. 

35  cc.  water. 

Put  in  a  liter  flask  150  grams  of  bleaching  powder 
(containing  33  per  cent,  available  chlorine) ,  add  450  cc. 
of  water,  and  insert  a  stopper  bearing  a  separatory  fun- 
nel, a  bent  tube  leading  to  a  condenser,  and  a  third  tube 
leading  nearly  to  the  bottom  of  the  flask.  Introduce 
through  the  separatory  funnel,  slowly  and  with  frequent 


120  ORGANIC    CHEMISTRY. 

shaking,  a  mixture  of  16  cc.  of  acetone  with  35  cc.  of 
water.  After  the  acetone  has  all  been  added  and  the 
flask  no  longer  grows  warm  spontaneously,  distil  the  re- 
mainder of  the  chloroform  by  passing  in  a  current  of 
steam.  Shake  the  chloroform  several  times  with  fresh 
quantities  of  water,  separate,  dry  by  allowing  to  stand 
with  fused  calcium  chloride,  and  distil  from  the  water- 
bath  without  separating  from  the  calcium  chloride. 
Yield  about  20  grams. 

Chloroform  is  a  colorless  liquid  with  an  ethereal  odor 
and  a  sweetish  taste.     It  boils  at  61°,  and  has  a  specific 

gravity  of    1.5039   at — ^—,  and  of  1.5264  at —5-      Pure 

4  4 

chloroform  decomposes  slowly,  especially  in  the  sun- 
light, with  liberation  of  chlorine,  hydrochloric  acid, 
phosgene,  and  other  substances.  The  addition  of  one 
per  cent,  of  alcohol  renders  it  more  stable.  Pure  chlo- 
roform should  not  impart  an  acid  reaction  to  water  with 
which  it  is  shaken,  nor  should  it  react  with  a  solution 
of  silver  nitrate  in  the  cold. 


CHAPTBR   IV. 


Nitro  Compounds* 

The  nitro  derivatives  of  aromatic  compounds  have 
been  longest  known  and  are  most  easily  prepared.  Un- 
til recently  it  was  thought  that  nitro  derivatives  of  hy- 
drocarbons of  the  marsh  gas  series  could  not  be  pre- 
pared by  the  direct  treatment  of  hydrocarbons  with 
nitric  acid.  Konowalow  has  shown,  however  (Ber.  d. 
chem.  Ges.,  28,  1852,  and  29,  2199),  that  such  com- 
pounds may,  in  many  cases,  be  prepared  by  the  use  of 
dilute  nitric  acid,  and  nitro  compounds  of  the  homologues 
of  benzene  may  be  prepared  containing  the  nitro  group 
in  the  side  chain  by  the  same  method. 

The  method  more  usually  employed  for  the  prepara- 
tion of  nitro  compounds  of  the  fatty  series  consists  in 
treating  alkyl  iodides  with  silver  nitrite. 

RI  +  AgNO9  =  R— NO9  +  Agl. 

With  aromatic  hydrocarbons  nitration  is  effected 
sometimes  by  adding  the  hydrocarbon  or  other  com- 
pound to  the  nitric  acid,  and  sometimes  by  the  reverse 
process. 

RH  +  HNO3  =  RNOa  +  H2O. 

As  the  reaction  is  accompanied  by  a  considerable  evo- 
lution of  heat,  the  mixture  must  usually  be  made  care- 
fully, and  in  many  cases  cooling  is  necessary.  The 


122  ORGANIC   CHEMISTRY. 

strength  of  acid  and  the  temperature  required  vary 
greatly  in  different  cases.  Sometimes  it  is  necessary  to 
reinforce  the  acid  by  the  use  of  a  mixture  with  concen- 
trated sulphuric  acid.  In  general  it  is  better  to  use  such 
a  mixture  and  moderate  the  action  by  cooling  rather 
than  to  use  nitric  acid  alone  at  a  higher  temperature. 
Benzene  derivatives  with  side  chains  are  more  easily 
nitrated  than  benzene  itself. 

The  nitro  group  usually  enters  in  the  para  or  ortho 
position  with  reference  to  CH3,  C2H6,  OH,  NH2,  Cl,  Br,  or 
I,  but  mainly  in  the  meta  position  toward  CO2H,  SO3H, 
CHO,  CN,  CC18,  or  NOQ.  In  the  case  of  the  amino 
group  it  is  sometimes  possible  to  cause  the  group  to  en- 
ter in  the  ortho  or  meta  position  at  will  by  changing  the 
conditions,  or  by  introducing  the  acetyl  group  in  the 
amino  group. 

In  order  to  secure  a  nitro  group  in  a  desired  position 
it  is  often  necessary  to  introduce  two  groups,  and  then 
eliminate  one  of  them  by  reduction  to  the  amino  group 
and  subsequent  elimination  of  the  latter  through  the 
diazo  reaction. 
R— N=N  +  C2H6OH  =  RH  +  C2H4O  +  HNO3  +  N2. 

NO3 

Primary  and  secondary  nitro  compounds  are  soluble 
in  solutions  of  alkalies  with  the  formation  of  salts  hav- 

ONa 
ing  the  structure,  =C=N^  (Nef  :      Ann.    Chem. 

O 

(Liebig),  280,263;  Ber.  d.  chem.  Ges.,  29,  1218). 
Tertiary  nitro  compounds,  and  nitro  compounds  of  the 


NITRO    COMPOUNDS.  123 

aromatic  series,  do  not  form  compounds  of  this  charac- 
ter. 

Mononitro  compounds  of  benzene  and  its  homologues 
are  volatile  with  water  vapor,  and  may  frequently  be 
separated  from  dinitro  compounds  and  other  substances 
by  this  means. 

The  reduction  of  nitro  compounds  to  amines  and  other 
bodies  will  be  considered  in  a  later  chapter. 

The  nitration  of  toluene  has  already  been  given  on  p. 
26. 

45.  Preparation  of  a  Dinitro  Compound  by  Direct 
Nitration.— w-Dinitrobenzene,  C6H4<^°»  fy' 

Literature.— Deville  :  Ann.  Chem.  Phys.,  [3],  3,  187  (1841)  ; 
Muspratt,  Hoffmann  :  Ann.  Chem.  (Liebig),  57,  214;  Beilstein, 
Kurbatow  :  Ibid,  176,  43  ;  Willgerodt :  Ber.  d.  chem.  Ges.,  25, 
608 ;  V.  Meyer,  Stadler :  Ibid,  17,  2649. 

20  grams  benzene  (23  cc.). 

50  cc.  nitric  acid  (1.42). 

50  cc.  concentrated  sulphuric  acid. 

100  cc.  concentrated  sulphuric  acid. 

Put  in  a  300  cc.  flask  20  grams  (23  cc.)  of  benzene 
and  add  in  small  portions  a  cooled  mixture  of  50 
cc.  of  nitric  acid  (sp.  gr.  1.42)  with  50  cc.  of  concen- 
trated sulphuric  acid.  Shake  vigorously  after  each  ad- 
dition and  cool  somewhat,  to  prevent  too  violent  a  reac- 
tion. When  the  mixture  has  all  been  added  and  the 
whole  shaken  vigorously  for  some  minutes,  add  in  small 
portions  and  shaking  as  before,  but  without  cooling,  100 
cc.  of  concentrated  sulphuric  acid.  Heat  to  about  120°, 


124  ORGANIC   CHEMISTRY. 

allow  to  cool  to  about  80°,  and  pour,  with  stirring,  into 
1500  cc.  cold  water.  Filter  off  the  dinitrobenzene  and 
crystallize  from  alcohol.  Yield  30  to  32  grams. 

Metadinitrobenzene  crystallizes  in  needles  which  are 
colorless  and  odorless.  It  melts  at  91°  and  boils  without 
decomposition  at  297°.  100  parts  of  alcohol  at  20°  dis- 
solve 3.5  parts.  Easily  soluble  in  hot  alcohol.  Prac- 
tically insoluble  in  water. 

46.  Preparation  of  a  Nitro  Derivative  of  an  Amine 
and  Elimination  of  the  Amino  Group. —  w-Nitro- 

tolnene,  C.H4 

Literature.— Mon net,  Reverdin,  Nolting  :  Ber.  d.  chem.  Ges., 
12,  443  ;  Nolting,  Witt :  Ibid,  18,  1336  ;  Buchka :  Ibid,  22,  829 ; 
Noyes,  Moses:  Am.  Chem.  J.,  7,  149;  Noyes:  Ibid,  10,475; 
Schraube,  Romig :  Ber.  d.  chem.  Ges.,  26,  579. 

20  grams  paraacettoluide. 

75  cc.  nitric  acid  (1.42). 

30  cc.  concentrated  sulphuric  acid. 

50  cc.  alcohol. 

10  grams  potassium  hydroxide. 

13  cc.  water. 

15  grams  nitrotoluidine. 

60  cc.  absolute  alcohol. 

12  cc.  concentrated  sulphuric  acid. 

8  (9  cc.)  grams  ethyl  nitrite. 

Prepare  accettoluide  by  boiling  paratoluidine  with 
twice  its  weight  of  glacial  acetic  acid  for  two  hours  (see 
acetanilide,  p.  86),  pouring  into  cold  water,  filtering  off, 


NITRO   COMPOUNDS.  125 

washing,  and  drying.  Add  20  grams  of  the  finely  pow- 
dered substance  in  small  portions  to  a  mixture  of  75  cc. 
of  nitric  acid  with  30  cc.  of  concentrated  sulphuric  acid. 
Stir  with  a  thermometer  during  the  addition,  and  keep 
the  temperature  between  30°  and  40°  by  setting  the 
beaker  in  cold  water.  When  all  has  been  added  allow 
the  beaker  to  stand  for  fifteen  minutes  and  then  pour  it 
into  cold  water,  filter  off  the  nitroacettoluide,  wash  and 
suck,  and  press  as  dry  as  possible  on  a  plate.  Put  the 
substance  in  a  flask,  add  50  cc.  of  alcohol,  heat  nearly 
to  boiling,  and  add,  carefully,  a  solution  of  10  grams  of 
potassium  hydroxide  in  13  cc.  of  water.  Heat  on  a 
water- bath  for  twenty  minutes.  Cool  thoroughly,  filter 
off  the  nitrotoluidine  on  a  plate,  wash  with  alcohol  di- 
luted with  two  volumes  of  water,  and  dry  thoroughly. 

Put  15  grams  of  the  nitrotoluidine  in  a  300  cc.  flask  and 
add  a  mixture  of  60  cc.  of  alcohol  with  12  cc.  of  concen- 
trated sulphuric  acid  while  the  latter  is  still  warm;  cool 
thoroughly,  and  add  slowly  with  vigorous  shaking  and 
cooling,  7.5  grams  of  ethyl  nitrite  (see  60,  p.  159).  Allow 
to  stand  a  few  minutes,  and  then  warm  on  the  water-bath 
till  the  evolution  of  nitrogen  ceases.  Cool,  precipitate 
the  nitrotoluene  by  adding  water,  siphon  off  or  decant 
most  of  the  aqueous  solution,  and  distil  the  nitrotoluene 
which  remains,  in  a  current  of  steam  (seei,p.  14).  A  small 
amount  of  nitrotoluene  may  be  obtained  by  extracting 
the  alcoholic  mother-liquors  with  ether,  but  in  most 
cases  it  is  not  worth  while  to  do  that.  Separate  the 
nitrotoluene  from  the  water  of  the  distillate,  and  dry  it  in 
vacua  over  sulphuric  acid.  Yield  8  to  10  grams. 


126  ORGANIC   CHEMISTRY. 

Instead  of  the  method  given  here,  Meyer  and  Jacob- 
son  advise  in  their  text-book  (Vol.  II,  p.  159)  to  dis- 
solve the  nitrotoluidine  in  a  mixture  of  three  parts  of 
alcohol  and  three  parts,  by  weight,  of  concentrated  sul- 
phuric acid,  cool,  add  the  theoretical  amount  of  sodium 
nitrite  dissolved  in  the  smallest  possible  amount  of  water, 
and  then  warm  on  the  water-bath  as  above.  In  the 
experience  of  this  laboratory  the  yields  obtained  in  this 
way  are  much  less. 

Instead  of  adding  ethyl  nitrite,  the  mixture  of  nitric 
oxide  and  nitrogen  peroxide  (usually  called  nitrous 
anhydride) ,  obtained  by  boiling  arsenious  oxide  with 
nitric  acid  (sp.  gr.  1.30-1.35),  may  be  passed  into  the 
acid  alcoholic  solution  till  it  smells  strongly  of  the  nitrous 
ester  after  standing  a  short  time,  or  ethyl  nitrite  may  be 
passed  in  as  it  is  generated  at  such  a  temperature  as  to 
assume  the  gaseous  form  (see  60,  p.  159). 

Paraacettoluide  crystallizes  in  rhombic  needles  which 
melt  at  153°.  It  boils  at  307°. 

3-Nitro-4-acettoluide  crystallizes  from  water  in  fine 
yellow  needles  which  melt  at  94°-95°- 

3-Nitro-4~toluidine  crystallizes  in  red  prisms,  which 
melt  at  Ii6°-ii7°.  It  is  volatile  with  water  vapor. 

Meta-nitrotoluene  melts  at  16°,  and  boils  at23O°-23i°. 
By  the  chromic  acid  mixture  it  is  oxidized  to  meta- 
nitrobenzoic  acid.  By  an  alkaline  solution  of  potas- 
sium ferricyanide  it  is  much  less  easily  oxidized  than 
ortho-  or  paranitrotoluene. 


NITRO   COMPOUNDS.  127 

NO, 


/\ 

/ 

47.  tf-Nitronaphthalene, 


Literature — Laurent:  Ann.  Chem.  (Liebig),  [21,59,378;  Beil- 
stein,  Kuhlberg :  Ibid,  169,  83 ;  Liebermann  :  Ibid,  183,  235  ; 
Piria  :  Ibid,  78,  32  ;  Aguiar :  Ber.  d.  chem.  Ges.,  5,  370. 

20  grams  naphthalene. 
100  grams  nitric  acid  (sp.  gr.  1.33). 
or 

55  cc.  nitric  acid  (sp.  gr.  1.42). 
25  cc.  water. 

Put  in  a  beaker  20  grams  of  naphthalene,  add  100 
grams  (75  cc.)  of  nitric  acid  (sp.  gr.  1.33),  and  allow  to 
stand  for  several  days.  Dilute  with  water,  filter,  wash 
and  dry.  Moisten  with  a  very  little  alcohol,  dissolve  in 
carbon  bisulphide,  filter  from  the  dinitro  compound,  and 
evaporate  the  solution  to  dryness.  (Beware  of  flames.} 
The  solution  can  be  evaporated  on  a  previously  heated 
water-bath  in  a  hood,  all  flames  in  the  neighborhood 
being  extinguished.  Recrystallize  from  alcohol.  Yield 
17  grams. 

<*-Nitronaphthaline  crystallizes  in  fine  yellow  needles 
which  melt  at  6 1 °.  It  boils  at  304°.  It  gives  by  oxi- 
dation nitrophthalic  acid,  while  the  aminonaphthalene 
obtained  by  its  reduction  gives  by  oxidation  phthalic 
acid. 


128  ORGANIC   CHEMISTRY. 

48.  Preparation  of  a  Nitro  Derivative  of  an  Am  inc. 

/CH3     (i). 

— /-amino-0-nitrotoluene,    C6Hg — NO2     (2). 

\NHa    (4). 

Literature. — Beilstein,  Kuhlberg :  Ann.  Chem.  (Liebig),  155, 
23;  Nolting  and  Collin  :  Ber.  d.  chem.  Ges.,  17, 263;  Noyes,  Moses: 
Am.  Chem.  J.,  7,  150. 

10  grams /-toluidine. 

100  grams  concentrated  sulphuric  acid  (sp.  gr.  1.84). 

7.5  grams  nitric  acid  (sp.  gr.  1.48). 

30  grams  concentrated  sulphuric  acid. 

500  cc.  ice  water. 

400  grams  acid  sodium  carbonate. 

Dissolve  10  grains  of  paratoluidine  in  200  grams  (120 
cc.)  of  cold  concentrated  sulphuric  acid.  Cool  to  o° 
with  a  freezing  mixture  (the  most  convenient  is  snow 
or  ice  and  concentrated  commercial  sulphuric  acid,  snow 
and  salt  is  a  little  cheaper) ,  and  drop  in  slowly  a  mix- 
ture of  7.5  grams  (5  cc.)  of  nitric  acid  (sp.  gr.  1.48), 
with  30  grams  (17  cc.)  of  concentrated  sulphuric  acid, 
stirring  and  keeping  the  temperature  below  5°.  Allow 
the  mixture  to  stand  for  half  an  hour,  and  pour  into  500 
cc.  of  ice  water,  keeping  the  temperature  below  25°. 
Filter,  add  1000  cc.  of  water  and  neutralize  with  baking 
soda.  About  400  grams  will  be  required.  Filter  off 
and  wash  the  precipitated  nitrotoluidine,  and  crystallize 
from  dilute  alcohol.  Yield  about  10  grams. 

In  this  nitration  the  large  amount  of  sulphuric  acid 
forms  an  acid  sulphate  with  the  toluidine,  and  appears  in 
that  way  to  so  change  the  character  of  the  amino  group 


NITRO   COMPOUNDS.  1 29 

that  the  nitro  group  enters  in  the  meta  position  with  re- 
gard to  it. 

Orthonitroparatoluidine    crystallizes    from    water  in 
broad,  yellow,  monoclinic  needles,  which  melt  at  77.5°. 


v. 


Amines* 

The  simplest  method  of  preparing  amines,  and  one 
which  usually  gives  pure  compounds,  consists  in  reduc- 
ing nitro  compounds. 

RNO3  +  6H  =  RNH2  +  2H2O. 

The  reducing  agents  generally  used  are  tin  and 
hydrochloric  acid,  iron  and  acetic  acid  (in  manufacture) , 
ammonium  sulphide,  and  stannous  chloride.  This  method 
of  preparation  is  general  with  aromatic  compounds,  but 
is  not  often  used  for  members  of  the  marsh  gas  series, 
because  of  the  difficulty  of  obtaining  the  nitro  com- 
pounds required. 

A  method  of  great  historical  importance  consists  in 
treating  halogen  derivatives  with  an  aqueous  solution  of 
ammonia. 

RBr  +  NH3  =  RNH2HBr. 

The  ease  with  which  secondary  and  tertiary  amines, 
and  quaternary  ammonium  salts  are  formed  by  this  re- 
action detracts  from  its  usefulness,  as  the  resulting 
mixtures  are  often  difficult  of  separation.  (For  a  method 
of  separation  see  page  85.) 

To  overcome  the  difficulty  which  arises  from  the 
formation  of  secondary  and  tertiary  amines  when  halo- 
gen compounds  are  treated  with  ammonia,  Gabriel  has 
used,  successfully,  potassium  phthalimide.  When  this 


AMINES.  131 

is  heated  with  halogen  compounds  to  i5o°-2oo°  in  sealed 
tubes  or  open  vessels,  according  to  the  nature  of  the 
halogen  compound,  derivatives  of  the  phthalimide  are 
formed.  These  may  be  saponified  with  separation  of 
the  chloride  of  the  primary  amine  by  heating  in  sealed 
tubes  at  200°,  with  three  parts  of  fuming  hydrochloric 
acid.  (Ber.  d.  chem.  Ges.,  20,  2224  ;  21,  566,  2669.) 

RC1  +  C6H4  <  cC>NK  =  C«H<  <CO>  NR  +  KCL 

C6H4<£°>NR+2H20  +  HC1  =  C«H<<COOH  + 
RNH2.HC1. 

Another  method  of  attaining  the  same  end,  which 
promises  to  be  very  general  in  its  application,  has  been 
worked  out  by  Delepine  (Compt  .Rend.,  120,  501  ;  124, 
292.)  On  heating  hexamethylene  amine  with  halogen 
compounds  in  solution  in  chloroform,  double  compounds 
are  produced.  When  these  are  heated  gently  with 
alcohol  and  concentrated  hydrochloric  acid  they  are  de- 
composed with  the  formation  of  a  primary  amine  and 
methylene-diethyl  ether. 


C6H12N4<R  +  i2C3H60+3HCl=3NH4Cl  + 

RNH,HC1  +  6CH,  <oc'H6' 

The  method  has  been  successfully  used  for  the  prep- 
aration of  benzyl  amine  and  of  allyl  amine,  and  is 
likely  to  prove  very  useful. 


132  ORGANIC   CHEMISTRY. 

A  more  useful  method  consists  in  the  reduction  of  ox- 
imes  and  hydrazones. 

*>C=NOH  +  4H  =  |,>CHNH1  +  H10. 

|,>C=NNHC.H.+  4H  =  |,  >  CHNH8  +  C.H.NH,. 

The  most  useful  reducing  agent  for  the  oximes  ap- 
pears to  be  absolute  alcohol  and  sodium.  The  same 
method  may  also  be  applied  to  hydrazones.  Or  the 
latter  may  be  reduced  by  zinc  dust  and  acetic  acid  in 
alcoholic  solutions. 

Nitriles  may  be  reduced  to  amines  by  absolute  alco- 
hol and  sodium,  and  in  some  cases,  also,  by  the  use  of 
zinc  and  hydrochloric  or  sulphuric  acid. 

R  —  C=N+4H  =  R— CH2NH2. 
When   acid    amides   are  treated  with   bromine   and 
sodium  hydroxide,  or,  in  many  cases,  if  treated  with  an 
alkaline  solution  of  sodium  hypobromite,  they  are  con- 
verted into  amines  with  loss  of  carbon  dioxide. 

R— CONH2  +  NaOBr  +  2NaOH  =  RNHa  +  NaBr  + 

HaO  +  Na2CO3. 

The  most  plausible  explanation  of  this  reaction  ap- 
pears to  be  that  given  by  Stieglitz,  based  on  the  work  of 
Nef  (Am.  Chem.  J.,  18,  751). 
R— CONH2  +  NaOBr  =  R— CO— NHBr  +  NaOH. 

R—  C=O 

\      w  +  NaOH  =  R—  C  =  O  +  NaBr  +  H2O. 

N<  I 


AMINES.  133 

R— C=O  C=O 

I  II  ; 

— N—  R— N 

CO  +  H20  =  RNH2  +  COa. 
An  illustration  of  this  reaction  has  been  given  in  a 
previous  chapter  (see  35»  p.  99). ' 

Aromatic  amines  may  sometimes  be  prepared  from 
phenols  by  heating  with  concentrated  ammonia  in  sealed 
tubes,  or  by  heating  with  ammonia  and  zinc  or  calcium 
chloride. 

ROH+  NH3  =  RNH2  +  H3O. 

Dimethyl  and  diethyl  amine  can  be  prepared  with  ad- 
vantage by  decomposing  />-nitrosodimethyl-  or  diethyl- 
aniline  with  caustic  soda. 

6)2  +  NaOH  =  C«H< 
NH(C,H5)2. 


49.  The  Preparation  of  an  Amine  by  the  Reduction 
of  a  Nitro  Compound. — Aniline,  C6HBNH2. 

Literature. — Unverdorbeu ;  Pogg.  Ann.,  8,  397  ;  Runge  :  Pogg. 
Ann.,  31,  65  ;  32,331;  Fritsche :  Ann.  Chem.  (Liebig),  36,  84; 
39,  76 ;  Anderson  :  Ibid,  70,  32  ;  Hoffmann  :  Ibid,  55,  200 ;  53, 
ii  ;  Wohler  :  Ibid,  102,  127;  Merz,  Weith:  Ber.  d.  chem.  Ges., 
13,  1298;  Merz,  Miiller  :  Ibid,  19,  2916  ;  Reverdin,  Harpe  :  Ibid, 
22,  1004. 

25  grams  nitrobenzene. 

45  grams  tin. 

100  cc.  commercial  hydrochloric  acid. 

1  For  a  modification  of  Hoffmann's  reaction  see  note,  p.  147. 


134  ORGANIC   CHEMISTRY. 

Put  into  a  500  cc.  flask  25  grams  of  nitrobenzene  and 
45  grams  of  tin.  Add  about  10  cc.  of  commercial  hydro- 
chloric acid  (sp.  gr.  1. 16),  and  shake  vigorously.  If  the 
solution  becomes  so  hot  as  to  boil,  cool  it  somewhat  by 
dipping  the  flask  in  cold  water.  When  the  reaction 
moderates  add  10  cc.  more  of  the  acid,  and  continue  in 
the  same  manner  till  100  cc.  have  been  added.  Warm 
on  the  water-bath  till  the  odor  of  nitrobenzene  disap- 
pears. Cool,  add,  with  further  cooling,  if  necessary, 
a  solution  of  75  grams  of  caustic  soda  in  100  cc.  of  water, 
and  distil  off  the  separates  aniline  with  water  vapor,  dis- 
tilling about  100  cc.  after  the  distillate  ceases  to  appear 
turbid.  Add  to  the  distillate  20  to  30  grams  of  salt  and 
some  ether,  separate  the  ethereal  solution,  dry  it  by 
allowing  it  to  stand  for  some  time,  best  over  night,  with 
some  powdered  caustic  potash,  pour  off  into  a  distilling 
bulb,  distil  the  ether  from  the  water-bath,  and  then  the 
aniline  with  a  free  flame.  Yield  15  to  17  grams. 

Aniline  is  a  colorless  oil  with  a  slightly  aromatic  odor. 
It  melts  at  — 8°,  boils  at  183.7°,  atld  has  a  specific 
gravity  of  1.036  at  o°,  and  1.0276  at  11.6°.  Aniline  forms 
salts  which  crystallize  well,  but  these  react  acid  toward 
test  papers.  Aniline  dissolves  in  31  parts  of  water  at 
12.5°.  The  chloride  is  easily  soluble  in  alcohol  and  in 
water,  and  melts  at  192°.  It  is  less  easily  soluble  in  hy- 
drochloric acid,  a  characteristic  which  may  be  used  with 
advantage  in  the  crystallization  and  purification  of  many 
of  the  chlorides  of  organic  bases.  Aqueous  solutions  of 
aniline  give  a  violet  color  on  the  addition  of  a  few  drops 
of  a  solution  of  calcium  hypochlorite  (chloride  of  lime). 


AMINES.  135 

50.  Preparation  of  a  Nitro-Amino  Compound  by 
the  Reduction  of  a  Dinitro  Compound. — p-amino-o- 

/CHS    (i). 

nitrotoluene,  C6H3— NO2   (2). 
\NH,  (4). 

Literature. — See  48,  p.  128 ;  also  Beilstein  and  Kuhlberg :  Ann. 
Chem.  (lyiebig),  155,  13. 

15  grams  toluene. 

35  cc.  nitric  acid   (1.42). 

35  cc   sulphuric  acid. 

75  cc.  sulphuric  acid. 

15  grams  dinitrotoluene. 

50  cc.  alcohol. 

8  cc.  ammonia  (0.90). 

Hydrogen  sulphide. 

Put  15  grams  of  toluene  in  a  small  flask  and  add  in 
small  portions,  70  cc.  of  a  mixture  of  equal  volumes  of 
concentrated  sulphuric  and  concentrated  nitric  acids, 
shaking  vigorously  and  cooling  somewhat.  After  the 
mixture  has  all  been  added  and  the  reaction  moderates, 
add  75  cc.  of  concentrated  sulphuric  acid,  shake  vigor- 
ously, heat  to  about  130°  and  keep  the  mixture  at  that 
temperature,  shaking  vigorously  for  about  15  minutes. 
Allow  to  cool,  pour  into  water,  filter,  wash,  and  crystal- 
lize the  dinitrotoluene  from  alcohol.  20  to  25  grams  of 
pure  dinitrotoluene,  melting  at  70.5°,  should  be  obtained. 

Put  15  grams  of  the  dinitrotoluene  in  a  flask,  add  50 
cc.  of  alcohol  and  8  cc.  of  concentrated  ammonia  (0.90), 
pass  in  a  rapid  current  of  hydrogen  sulphide  nearly  to 
saturation,  connect  the  flask  with  a  reversed  condenser 


136  ORGANIC   CHEMISTRY. 

or  condensing  tube,  and  heat  on  a  water-bath  for  half  an 
hour.  Cool,  saturate  again  with  hydrogen  sulphide,  and 
heat  as  before.  Filter  hot,  cool  the  filtrate,  add  water, 
and  filter  off  the  precipitated  nitrotoluidine  after  stand- 
ing for  some  time.  Purify  by  dissolving  in  dilute 
hydrochloric  acid,  filtering,  and  precipitating  again  with 
ammonia.  Yield  about  10  grams. 

Orthonitroparatoluidine  crystallizes  from  water  in 
broad  yellow  monoclinic  needles,  which  melt  at  77.5°. 
It  is  difficultly  soluble  in  water  and  carbon  bisulphide, 
easily  soluble  in  alcohol  and  acids. 

51.  Preparation  of  a  Diamino  Derivative  of  Benzene. 


—  ^-Phenylendiamine,    C6H4<3    fa      (/-Diamino- 


benzene)  . 

Literature.—  Grethen  :  Ber.  d.  chem.  Ges.,  9,  775  ;  Beilstein, 
Kurbatow  :  Ann.  chem.  (Liebig),  197,  83:  Nolting,  Collins: 
Ber.  d.  chem.  Ges.,  17,  262;  Hobrecker  :  Ibid,  5,  920. 

20  grams  acetanilid. 

75  cc.  nitric  acid  (1.42). 

30  cc.  sulphuric  acid  (1.84). 

20  grams  nitro  acetanilide. 

30  grams  tin. 

80  cc,  commercial  hydrochloric  acid. 

Hydrogen  sulphide. 

Lime. 

Prepare  ^-nitroacetanilide  exactly  as  directed  for  nitro- 
acettoluide  (see46,p.  124).  Put  in  a  flask  20  grams  of  nitro- 
acetanilide  and  30  grams  of  tin.  Add  10  cc.  of  concentra- 


AMINES.  137 

ted  commercial  hydrochloric  acid,  and  shake  till  the  reac- 
tion begins  to  moderate;  add  more  of  the  acid  and  shake  as 
before,  and  continue  till  80  cc.  of  acid  have  been  added. 
Then  heat  on  the  water-bath  till  the  reaction  is  com- 
plete. The  nitro  group  is  reduced  and  the  acetyl  group 
is  also  removed.  Dilute  with  three  or  four  volumes  of 
water,  pour  off  from  any  undissolved  tin,  precipitate  the 
tin  from  the  solution  with  hydrogen  sulphide,  and 
filter  on  a  Witt  plate  or  Hirsch  funnel  (see  3,  p.  21). 
The  hydrogen  sulphide  is  best  generated  in  a  two- 
liter  acid  bottle  from  considerably  more  than  the 
theoretical  amount  of  iron  sulphide,  which  is  placed 
in  the  bottle  with  1500  cc.  of  water.  Somewhat  more 
than  the  theoretical  amount  of  concentrated  com- 
mercial sulphuric  acid  is  then  added,  in  small  portions, 
through  the  thistle  tube.  The  gas  should  be  passed 
through  a  washing  tube  or  wash-bottle  containing  a  lit- 
tle water.  After  the  operation  is  over,  the  generator 
should  be  emptied  at  once,  as  the  ferrous  sulphate  would 
crystallize  on  standing.  If  any  unused  ferrous  sulphide 
is  left  in  the  bottle,  and  the  latter  is  filled  up  at  once  with 
water  to  prevent  its  oxidation,  it  can  be  saved  for  use 
again. 

Evaporate  the  filtrate  to  a  small  volume,  filter  again, 
if  necessary,  through  a  hardened  filter,  and  allow  the 
chloride  of  the  phenylene  derivative  to  crystallize. 

To  prepare  the  free  amine,  mix  the  chloride  with  an 
equal  weight  of  quicklime,  and  distil  from  a  small  re- 
tort. The  paraphenylenediamine  may  be  recrystallized 
from  benzene.  Yield  10  to  12  grams. 


13  ORGANIC    CHEMISTRY. 

Paradiaminobenzene  crystallizes  from  benzene  in  shin- 
ing leaflets,  which  melt  at  140°  and  boil  at  267°.  It  is 
moderately  soluble  in  hot  water. 

Paranitroacetanilide  melts  at  207°. 

52.  Preparation  of  an  Amine  by  the  Decomposition 
of  an  Alkyl  Derivative  of  Aniline. — Diethylamine, 
(C9HJ3NH. 

Literature.— Hoffmann  :  Ann.  Chem.  (Liebig),  74,  128,  135  ; 
Elsbach :  Ber.  d.  chem.  Ges.,  15,  690;  Piutti :  Ann.  Chem. 
(Liebig),  227,  182;  Pictet:  Ber.  d.  chem.  Ges.,  20,  3422;  Schloe- 
mann  :  Ibid,  26,  1020;  Reynolds  :  J.  Chem.  Soc.,  6x,  457  ;  Kopp  : 
Ber.  d.  chem.  Ges.,  8,  621 ;  L,ippmann  u.  Fleissner :  Ibid,  16, 
1422  ;  Hoffmann  :  Ann.  Chem.  (Liebig),  73,  91  ;  Wallach  :  Ibid, 
214,  275;  Reinhardt  and  Staedel:  Ber.  d.  chem.  Ges.,  16,  29  ; 
Baeyer  and  Caro  :  Ibid,  7,  963. 

30  grams  aniline. 

45  grams  ethyl  bromide. 

20  grams  sodium  hydroxide. 

60  cc.  water. 

35  grams  ethyl  aniline. 

45  grams  ethyl  bromide. 

20  grams  sodium  hydroxide. 

60  cc.  water. 

30  grams  diethylaniline. 

150  cc.  water. 

120  cc.  concentrated  hydrochloric  acid  (1.19). 

zoo  grams  ice. 

1 6  grams  sodium  nitrite. 

80  cc.  water. 

70  grams  sodium  hydroxide. 

210  cc.  water. 


AMINES.  139 

Put  in  a  small  flask  30  grams  of  aniline  and  45  grams 
of  ethyl  bromide,  and  heat  with  a  reversed  condenser  for 
one  or  two  hours,  or  until  the  mass  solidifies.  Cool,  add 
60  cc.  of  a  solution  of  sodium  hydroxide  (3  cc.  =  i 
gram),  with  cooling,  separate  the  ethyl  aniline,  add  to  it 
45  grams  of  ethyl  bromide,  and  heat  with  reversed  con- 
denser as  before,  till  the  mass  solidifies.  Dissolve  in 
water,  boil  to  expel  any  ethyl  bromide  which  remains, 
cool,  add  60  cc.  of  caustic  soda,  and  separate  the  diethyl 
aniline.  Dry  with  powdered  potassium  hydroxide,  and 
distil,  collecting  as  much  as  possible  of  the  portion  boil- 
ing at  2i2°-2i5°.  (Aniline  boils  at  183.7°,  ethyl  ani- 
line at  206°,  and  diethyl  aniline  at  213.5°.) 

Dissolve  30  grams  of  the  diethyl  aniline  in  120  cc.  of 
concentrated  hydrochloric  acid  and  150  cc.  of  water, 
cool,  add  loo  grams  of  ice,  and  when  the  solution  is  near 
o°  add  slowly,  with  stirring,  16  grams  of  sodium  nitrite 
dissolved  in  80  cc.  of  water.  After  an  hour  transfer  the 

solution  of  nitrosodiethyl  aniline,  C6H4<C^/£  H  )  '  tO 

a  liter  flask  and  add  carefully,  with  shaking,  210  cc.  of 
a  strong  solution  of  sodium  hydroxide,  connect  with  a 
condenser  by  means  of  a  bent  tube,  and  distil,  collecting 
the  distillate  in  a  flask  containing  20  cc.  of  concentrated 
hydrochloric  acid.  The  solution  remaining  in  the  flask 
may  be  used  for  the  preparation  of  paranitrosophenol. 

The  hydrochloric  acid  solution  will  contain  diethyl- 
ammonium  chloride,  some  ethyl  aniline  regenerated  from 
nitrosoethyl  aniline  which  has  distilled  over,  some  di- 
ethyl aniline,  and  probably  other  substances.  Evapo- 


14°  ORGANIC   CHEMISTRY. 

rate  on  the  water-bath  to  about  50  cc.,  transfer  to  a  200 
cc.  flask,  cool  thoroughly,  dd,  with  cooling,  60  cc.  of 
sodium  hydroxide  (3  cc.  i  gram),  connect  the  flask 
by  means  of  a  tightly  i  ng  cork,  with  a  glass  tube 
one  cm.  in  diameter  r  bout  60  cm.  long,  and  held 
in  a  clamp  at  an  ang  5°  with  the  perpendicular. 

About  15  cm.  of  the  .jjer  end  of  the  tube  should 
be  bent  downward  and  this  should  dip  into  a  flask 
containing  10  cc.  of  concentrated  hydrochloric  acid. 
If  the  lower  portion  of  the  tube  is  filled  with  glass 
beads  a  better  separation  will  be  effected.  Distil  very 
slowly,  in  such  a  manner  that  the  ethyl  aniline  and 
similar  substances  almost  entirely  condense  and  run 
back.  Sometimes  it  may  be  necessary  to  neutralize  the 
distillate  with  50  cc.  of  sodium  hydroxide,  and  distil 
again  before  a  pure  distillate  can  be  obtained.  Finally 
evaporate  the  solution  of  diethylammonium  chloride 
nearly  or  quite  to  dryness,  transfer  to  a  flask  or  distil- 
ling bulb,  decompose  with  a  very  concentrated  solution 
of  sodium  or  potassium  hydroxide,  and  distil  from  the 
water-bath.  To  obtain  the  amine  free  from  water  it 
must  be  dried  with  fused  caustic  potash  and  distilled 
again.  Yield  7  to  8  grams. 

Diethyl  amine  boils  at  55°-56°,  and  has  a  specific  grav- 
ity of  0.7028  at  25°.  The  chloride  melts  at  2i5°-2i7°, 
boils  at  32o°-33o°,  and  is  very  easily  soluble  in  water, 
but  difficultly  soluble  in  absolute  alcohol. 

53.    Preparation   of    an   Amine   from   an   Oxime. — 

QTT  NTT 

Isopropyl  amine,  pj-r3>C<j-]     * '    (2~amino  propane.) 


AMINKS.  141 

Literature. — Sierch  :  Ann.  Chem.  (Liebig),  148,  263 ;  Gautier ; 
Ann.  Chim.  Phys.,  [4],  i7>  251  ;  Hoffmann  :  Ber.  d.  chem.  Ges., 
15,  768  ;  Tafel :  Ibid,  19,  1926  ."  Goldschmidt :  Ibid,  20,  728  ; 
Noyes  ;  Am.  Chem.  J.,  14,  226;  -540. 

. 
10  grams  acetoxime. 

20  grams  sodium. 

240  cc.  absolute  alcohol. 

Put  in  a  200  cc.  round-bottomed  flask  20  grams  of 
sodium,  connect  with  a  long  reversed  condenser,  and 
pour  through  the  latter  a  solution  of  10  grams  of  acet- 
oxime in  60  cc.  of  absolute  alcohol.  By  means  of  a 
short  tube,  bent  twice  at  right  angles  and  passing  through 
rubber  stoppers,  connect  the  top  of  the  condenser  with  a 
U-tube  containing  5  to  6  cc.  of  concentrated  hydrochloric 
acid.  Because  of  the  low  boiling-point  of  isopropyl 
amine  this  is  necessary,  but  with  amines  of  higher 
molecular  weight  it  is  not  required.  When  the  first 
violent  action  slackens,  warm  on  an  asbestos  plate  and  add 
from  time  to  time,  more  alcohol,  whenever  a  crust  forms  on 
the  sodium.  About  240  cc.  of  alcohol  will  be  required. 
When  the  sodium  has  all  dissolved,  add  40  cc.  of  water 
through  the  condenser,  cool,  and  then  distil  off  the  alco- 
hol and  isopropyl  amine,  collecting  in  a  flask  contain- 
ing 12  cc.  of  concentrated  hydrochloric  acid,  including 
that  from  the  []-tube.  Evaporate  to  dry  ness,  and  pre- 
serve the  amine  in  the  form  of  its  chloride.  Yield  8  to 
10  grams. 

Isopropyl  amine  boils  at  31.5°,  and  has  an  ammoniacal, 
fishy  odor.  Its  specific  gravity  is  0.690  at  18°.  The 
chloride  is  deliquescent  and  melts  at  i53°-i55°.  The 


S 


142  ORGANIC    CHEMISTRY. 

chloroplatinate  is  difficultly  soluble,  and  melts  at  227°- 
228°.  The  salt  is  easily  prepared  by  adding  chloropla- 
tinic  acid,  ("platinic  chloride"),  H2PtCl6,  to  a  concen- 
trated solution  of  the  chloride.  It  can  be  analyzed  by 
careful  ignition  in  a  porcelain  crucible. 

54.  Preparation  of  an  Amine  by  the  Reduction  of 

a  Cyanide.— cw-Phenyl-ethyl-amine,  C6H5CH2CH3NHa. 
( 1 8-amino-ethy  Iphen . ) 

Literature. — Cannizzaro :  Ann.  Chem.  (Liebig),  96,  247; 
Mann  ;  Ber.  d.  chem.  Ges.,  14,  1645 ;  Stadel :  Ibid,  19,  1951  ; 
Hotter  :  Ibid,  20,  82  ;  Spica,  Columbo  ;  Gaz.  chim.  Ital.,  5,  124  ; 
Bernsthen  :  Ann.  Chem.  (Liebig),  184,  304;  Ladenburg:  Ber. 
d.  chem.  Ges.,  18,  2956 ;  8,  19,  782  ;  Hoffmann :  Ibid,  18,  2740 ; 
Hoogewerf,  van  Dorp;  Rec.  trat.  chim  des  Pays-Bas.,  5,  254; 
Fileti,  Piccini:  Ber.  d.  chem.  Ges.,  12,1700. 

30  grams  benzyl  chloride. 
38  cc.  alcohol. 

1 8  grams  potassium  cyanide. 
17  grams  water. 

5  grams  benzyl  cyanide. 

6  grams  sodium. 

70  cc.  absolute  alcohol. 

8  cc.  hydrochloric  acid  (sp.  gr.  i.io). 

Put  in  a  round-bottomed  flask  18  grams  of  pure  pow- 
dered potassium  cyanide,  17  cc.  of  water,  30  grams  of 
benzyl  chloride,  and  38  cc.  of  alcohol.  Connect  with  an 
upright  condenser,  and  boil  on  a  wire  gauze  or  asbestos 
plate  for  3  to  4  hours.  By  means  of  a  separatory  funnel 
separate  the  alcoholic  solution,  containing  the  benzyl 
cyanide,  from  the  lower  aqueous  layer  and  distil  the 


AMINES.  143 

former.  The  alcohol  and  water  may  be  distilled  with 
advantage  from  a  water-bath  under  diminished  pressure 
and  the  heating  continued  till  the  residual  liquid  is  dry 
(see  7,  p.  36).  In  any  case  the  portion  boiling  at  210°— 
240°  will,  if  dry,  be  sufficiently  pure  for  this  prepara 
tion  .Yield  of  benzyl  cyanide  20  to  22  grams. 

Put  in  a  200  cc.  round- bottomed  flask  6  grams  of 
sodium,  cut  in  small  pieces,  add  a  warm  solution  of  5 
grams  of  benzyl  cyanide  in  30  cc.  of  absolute  alcohol, 
connect  with  an  upright  condenser,  and  heat  rapidly  to 
boiling.  Continue  to  boil  and  add  more  alcohol  as 
necessary,  in  all  70  to  80 cc.,  till  the  sodium  is  dissolved. 
Distil  off  the  alcohol  and  the  phenylethylamine  in  a  cur- 
rent of  steam,  distilling  as  long  as  the  distillate  comes 
over  alkaline.  Add  to  the  distillate  8  cc.  of  hydro- 
chloric acid,  evaporate  to  a  small  volume,  filter,  and 
evaporate  to  dryness.  Transfer  the  residue  to  a  small 
test-tube,  dissolve  in  2  to  3  cc.  of  hot  water,  cool,  add  8 
cc.  of  sodium  hydroxide  (3  cc.  =  i  gram),  and  a  few  cc. 
of  ether,  and  shake  vigorously.  Allow  the  ethereal  layer 
to  separate,  and  by  means  of  a  pipette  with  a  fine  capil- 
lary tube,  remove  as  much  as  possible  of  the  aqueous 
solution  from  below.  Pour  off  the  ethereal  solution  into 
a  dry  tube,  rinse  with  a  little  ether,  and  dry  the  ethereal 
solution  by  adding  solid  caustic  potash  and  leaving  it 
for  24  hours.  Transfer  to  a  small  (15  cc.  or  less)  dis- 
tilling bulb,  and  distil  the  ether  through  a  condenser  and 
then  the  amine  directly  into  a  small  preparation  tube. 
Yield  about  2\  grams  of  the  chloride,  and  \\  grams  of 
the  distilled  amine. 


144  ORGANIC   CHEMISTRY. 

This  method  of  reducing  cyanides  led  Ladenburg  to 
the  synthesis  of  cadaverin  from  trimethylene  cyanide, 
CNCH2CH2CH2CN.  With  ethylene  cyanide  and  phenyl 
cyanide  it  gives  less  satisfactory  results,  owing,  in  the 
latter  case,  to  secondary  reactions  which  give  partly 
benzene  and  sodium  cyanide  and  partly  sodium  benzoate 
and  ammonia. 

Benzyl  cyanide  boils  at  231.7°.  6?-phenyl-ethylamine 
is  a  colorless  liquid  which  has  a  slightly  ammoniacal 
odor,  and  boils  at  198°.  It  has  a  specific  gravity  of  0.958  at 
24.4°.  It  is  a  strong  base,  is  somewhat  soluble  in  water, 
and  is  easily  soluble  in  alcohol  and  ether.  The  chloride, 
C6HBCH2CH2NH2HC1,  crystallizes  from  absolute  alco- 
hol in  leaflets  or  plates,  which  melt  at  217°,  and  dis- 
solve in  1 1  parts  of  water  at  14°.  It  is  less  easily  solu- 
ble in  hydrochloric  acid,  easily  soluble  in  alcohol. 
The  chloroplatinate  is  difficultly  soluble  in  cold  water. 

55.  Benzyl  Amine.— C6H6CHaNH3,  Aminomethyl- 
phen. 

Literature. — Mendius :  Ann.  Chem.  (Liebig),  lai,  144;  Bam- 
berger,  Lodter;  Ber.  d.  chem.  Ges«,  20,  1709  ;  Cannizzaro  :  Ann. 
Chem.  (Liebig),  134,  128 ;  Hofmann  :  Ber.  d.  chem.  Ges.,  18, 
2738;  Tafel :  Ibid,  19,  1928;  Curtius,  L,ederer :  Ibid,  19,  2463; 
Iveuchart,  Bach :  Ibid,  19,  2128;  Goldschmidt:  Ibid,  19,  3232; 
Mason:  J.  Chem.  Soc.,  63,  1313;  Seelig :  Ber.  d.  chem.  Ges.,  23, 
2971  ;  Hoogewerf,  van  Dorp  :  Rec.  tran.  chim.  d.  Pays.  Bas.,  5, 
253  ;  Delepine  :  Compt.  rend.,  120,  501  ;  124,  292. 

50  cc.  formaldehyde  solution  (40  per  cent.). 
50  cc.  ammonia  (sp.  gr.  0.90). 


AMINKS.  145 

10  gram  hexamethlene  amine. 

10  grams  benzyl  chloride. 

30  cc.  chloroform. 

1 6  grams  double  compound  of  hexamethylene  amine 
with  benzyl  chloride. 

45  cc.  alcohol. 

15  cc.  concentrated  hydrochloric  acid. 

Put  in  a  150  cc.  distilling  bulb  50  cc.  of  a  40  per  cent, 
solution  of  formaldehyde  and  add  in  small  portions, 
cooling  somewhat,  50  cc.  of  ammonium  hydroxide  (0.90). 
Heat  for  5  to  10  minutes  on  a  water-bath ,  put  in  the 
mouth  of  the  bulb  a  rubber  stopper  bearing  a  fine  capil- 
lary tube  (see  10,  p.  46),  and  distil  as  rapidly  as  possible 
from  the  water-bath,  under  diminished  pressure,  till  the 
residue  of  hexamethylene  amine  appears  dry.  Rinse  out 
the  amine  with  a  mixture  of  two  volumes  of  ether  with 
one  volume  of  alcohol  and-  suck  off  on  a  Witt  plate. 
Wash  with  a  little  ether  and  dry  on  the  water-bath.  10 
grams  of  the  amine  should  be  obtained.  A  small  addi- 
tional quantity  of  amine  may  be  obtained  from  the  alco- 
hol-ether mother-liquors. 

Put  in  a  small  flask  10  grams  of  the  hexamethylene 
amine,  30  cc.  of  chloroform,  and  10  grams  of  benzyl 
chloride.  Connect  with  an  upright  condenser,  and  boil 
gently  on  a  water-bath  for  half  an  hour.  Allow  to  cool, 
filter,  and  wash  with  a  little  chloroform.  About  16 

OTT  r\  TT 

grams  of  the  double  compound,  C6H18N4<;£j *    <    6  , 
should  be  obtained.     An  additional  small  amount  of  the 
compound   will   separate   from   the   mother-liquors    on 
standing. 


146  ORGANIC   CHEMISTRY. 

Put  in  a  distilling  bulb  16  grams  of  the  double  com- 
pound last  mentioned,  and  60  cc.  of  a  mixture  of  three 
volumes  of  alcohol  and  one  volume  of  concentrated 
hydrochloric  acid.  Connect  with  an  upright  condenser, 
and  heat  on  a  water-bath  for  an  hour,  then  distil  from 

OC  H 
2B 


the  water-bath  the  methylenediethyl  ether, 

which  has  been  formed.  Add  to  the  residue  20  cc.  of 
the  same  mixture  of  alcohol  and  hydrochloric  acid,  and 
heat  again  for  an  hour  on  the  water-bath,  allowing  the 
methylenediethyl  ether  to  distil  through  a  condenser  as 
it  is  formed.  Then  distil  over  a  free  flame  till  20  to  25 
cc.  in  all  have  passed  over.  Repeat  this  process  a 
second  time,  and,  if  necessary,  a  third,  or  till  the  odor 
of  the  ether  can  no  longer  be  detected  in  the  distil- 
late. The  complete  decomposition  of  the  double  com- 
pound is  essential  to  the  success  of  the  preparation. 

Transfer  the  residue  in  the  bulb  to  an  evaporating 
dish,  and  evaporate  on  the  water-bath  nearly  or  quite  to 
dryness  .  Transfer  the  residue  to  a  flask  ,  add  a  strong  solu- 
tion of  sodium  hydroxide  in  considerable  excess,  separate 
the  benzyl  amine  by  means  of  a  separatory  funnel,  dry 
it  by  allowing  it  to  stand  with  solid  caustic  potash,  and 
distil.  Yield  4  to  5  grams.  In  working  with  larger 
quantities  the  yield  is  somewhat  better. 

The  methylenediethyl  ester,  which  is  formed  as  a  by- 
product, boils  at  89°,  and  has  a  specific  gravity  of  0.851 
at  o°.  It  dissolves  in  n  volumes  of  water  at  18°. 

Benzyl  amine  boils  at  183°,  and  has  a  specific  gravity 


AMINES.  147 

of  0.9826  at       '%  '      It  is  miscible  in   all  proportions 

4 

with  water,  alcohol,  and  ether,  but  is  separated  from 
aqueous  solutions  on  the  addition  of  sodium  hydroxide. 
It  has  a  strong  alkaline  reaction,  and  absorbs  carbon 
dioxide  from  the  air. 


NOTE  .  — An  important  modification  of  Hoffmann '  s  reac- 
tion came  to  the  author's  notice  too  late  for  insertion  at 
the  appropriate  place  in  this  chapter  (p.  133). 

Lengfeldt,  Stieglitz,  and  Elizabeth  Jeffreys  have  very 
recently  shown  (Ber.  d.  chem.  Ges.,  30,  898;  see  also 
Am.  Chem.  J.,  15,  215,  504;  16,  307  ;  19,  295)  that  in 
the  case  of  aliphatic  amides  of  high  molecular  weights, 
where  the  reaction  cannot  be  applied  in  its  usual  form 
owing  to  the  formation  of  nitriles,  the  urethane  can  be 
obtained  by  dissolving  the  amide  (i  molecule)  in  3  parts 
of  methyl  alcohol,  adding  a  solution  of  sodium  (2  atoms) 
in  25  parts  of  methyl  alcohol,  and  dropping  bromine  (2 
atoms)  into  the  solution.  After  warming  for  ten  minutes 
on  the  water-bath,  the  solution  is  acidified  with  acetic 
acid,  evaporated,  the  inorganic  salts  removed  with  water 
and  the  urethane  separated  from  unchanged  amide  by 
solution  in  warm  ligroin.  The  urethane  is  decomposed 
by  heating  with  concentrated  sulphuric  acid  at  i  io°-i2o° 
for  an  hour,  or,  better,  by  distilling  with  three  to  four 
times  its  weight  of  slaked  lime. 

RCONHBr+NaOCHs=  RNHCOOCH3  +  NaBr. 

Urethane. 

RNHCOOCH3  +  Ca(OH)2  =  RNH2+CaCOs+CH3OH. 


CHAPTKR   VI. 


Diazo,  Hydrozo,  Nitroso  and  Other  Nitrogen  Compounds* 

A  considerable  number  of  other  nitrogen  compounds 
beside  amines  and  nitro  derivatives  are  known.  Most 
of  these  are  obtained  by  reduction  of  nitro  compounds, 
by  oxidation  of  amines,  or  by  condensations  with  the  use 
of  the  compounds  resulting  from  such  reduction  or  oxi- 
dation. Unless  otherwise  stated,  the  following  methods 
apply  to  the  aromatic  series  only.  In  some  cases  simi- 
lar derivatives  of  the  marsh  gas  series  are  known,  but 
usually  they  require  different  methods  of  preparation. 

Azoxy  compounds  are  formed  by  boiling  nitro  com- 
pounds with  a  solution  of  caustic  potash  in  methyl  or 
ethyl  alcohol,  or  with  a  solution  of  sodium  ethylate,  or 
methylate,  the  alcohol  acting  as  the  reducing  agent. 

2R— N03  —  3O  =  R— N— N— R. 
\/ 
O 

The  method  cannot  be  applied  to  compounds  having 
a  methyl  group  para  to  the  nitro  group,  because  conden- 
sation to  derivatives  of  dibenzyl,  C6H5CH2CH3C6H6,  or 
stilbene,  C6HBCH=CHC6H5,  takes  place. 

Azo  compounds  are  prepared  by  the  reduction  of 
azoxy  compounds  by  distillation  with  iron  filings,  by  the 
direct  reduction  of  nitro  compounds  with  zinc  dust  and 
alcoholic  potash,  or  by  the  oxidation  of  a  hydrazo  com- 
pound by  means  of  the  oxygen  of  the  air  acting  on  a 
solution  in  alcohol  containing  a  little  alkali. 


NITROGEN    COMPOUNDS.  149 

R— N— N— R— O  =  R— N=N— R. 
\/ 
O 

2R— N02  — 40  =  R— N=N— R. 
R— NH— NH— R+O  =  R— N=N— R+H9O. 

Aminoazo,  R — N=N — R — NH2,  and  oxyazo  (more 
correctly  hydroxyazo),  R — N=N — R — OH,  compounds 
are  formed  by  the  condensation  of  diazo  compounds, 
with  amines  or  phenols.  As  the  condensation  takes 
place  usually  in  neutral,  or  slightly  acid  solutions,  but 
does  not,  as  a  rule,  occur  in  either  strongly  alkaline  or 
strongly  acid  solutions,  Bamberger  supposes  the  reaction 
to  take  place  between  the  diazo  hydroxide  and  the  other 
compound.  (Ber.  d.  chem.  Ges.,  28,  444.) 
R— N=N— OH  +  H— R— NH2  =  R— N=N— R— NHa 
+  H90. 

This  kind  of  condensation  takes  place  most  readily 
with  tertiary  amines,  and  with  primary  metadiamines. 
Primary  and  secondary  amines,  on  the  other  hand,  con- 
dense in  acetic  acid  solutions,  with  the  formation  of 
diazoamino  compounds. 

R— N=N— OH  +  R— NH,  =  R— N=N— NHR+H9O. 
These  diazoamino  compounds,  when  allowed  to  stand 
with  cold  dilute  hydrochloric  acid,  or  when  warmed  with 
the  chloride  of  the  amine,  dissolved  in  the  free  amine, 
usually  pass  over  into  the  corresponding  amino-azo  com- 
pound ;  e.  g.  : 

C6H5—  N=N— NHC6H5  —  C.H.— N=N— C.H.NH,. 
Diazoamino  benzene.  Aminoazobenzene. 


150  ORGANIC   CHEMISTRY. 

This  combination  ("  Kuppelung  ")  of  diazo  compounds 
with  amines  and  phenols,  and  the  transformation  of 
diazoamino  into  aminoazo  compounds,  are  of  great 
technical  importance.  O.  N.  Witt  has  pointed  out  that 
dye-stuffs  must  have  two  characteristics  ;  they  must 
have  a  color  group  ("  chromophor  " ) ,  e.  g.,  the  azo,  or 
nitro  group,  and  they  must  also  have  a  salt-forming 
group  ("auxochrome"),  e.  g.,  hydroxyl,  or  the  amino 
group,  which  will  enable  the  substance  to  combine  with 
the  fiber  in  dyeing.  The  azo  compounds  are  all  of  them 
colored,  but  only  those  of  them  which  contain  some 
"auxochrome  "  group  as  well  can  be  used  in  dyeing. 

All  organic  coloring  matters  are  changed  to  colorless 
compounds  by  reduction.  These  colorless  compounds 
have  received  the  general  name  of  ' '  leuco  ' '  compounds 
("L,eukoverbindungen,"  from  Greek  XSVKOS,  white). 
The  leuco  compounds  corresponding  to  the  azo  bodies 
are  the  hydrazo  compounds.  These  may  be  prepared 
from  the  azo  compounds  by  reduction  with  alcoholic 
ammonium  sulphide,  or  with  zinc  dust  and  alcoholic 
potash  or  soda.  They  may  also  be  prepared  by  direct 
reduction  of  nitro  compounds  with  zinc  dust  and  alco- 
holic potash. 

R— N=N— R+  2H  =  R— NH— NH— R. 
2R—  N0a+  ioH  =  R-NH— NH— R  +  4H2O. 

Diazo  compounds  are  formed  by  the  action  of  nitrous 
acid  on  amines  in  acid  solutions. 

RNH2HC1  +  HNO2  =  R— N=N+2H,O. 

Cl 


NITROGEN   COMPOUNDS. 


UNIVERSITY 


151 


On  account  of  their  instability,  diazo  compounds  are 
not  usually  separated,  but  are  used  for  synthetical  pur- 
poses immediately  after  preparation.  Several  illustra- 
tions of  such  use  have  already  been  given.  (See  pp.  42, 
114,  224,  and  168.) 

Hydrazines  are  prepared  by  the  reduction  of  diazo 
compounds  with  stannous  chloride,  with  acid  sodium 
sulphite,  or  with  acid  sodium  sulphite,  zinc  dust  and 
acetic  acid,  followed  by  the  decomposition  of  the  result- 
ing sulphonic  acid  with  hydrochloric  acid. 
R—  NEEEN  +  2SnCl,  +  4HC1  =  R—  NH—  NH,HC1  + 

Cl 

2SnCl4. 

R—  N=N  +  HNaSOs  =  R—  N=N—  SO3Na  +  HC1. 

Cl 

R_N=rN—  S03Na+2H  =  R—  NH—  NH—  SO3Na. 
R—  NH—  NH—  S03Na  +  HC1+H2O= 

R—  NH—  NH2HC1  +  NaHS04. 

Hydrazones  are  formed  by  the  condensation  of  hydra  - 
zines  with  aldehydes  or  ketones,  usually  in  neutral  or 
acetic  acid  solution. 

R  /R 

R_NH—  NH3  +      ;CO  =  R—  NH—  N=C'     +  H2O. 

RX  NR 

Hydrazones  are  also  formed  by  the  condensation 
of  diazo  compounds  with  bodies  containing  a  methylene 
group  between  two  carboxyl  groups.  Owing  to  a  differ- 
ent view  of  the  structure  of  these  compounds,  which 


J52  ORGANIC   CHEMISTRY. 

prevailed  before  they  had  been  fully  studied,  they  are 
frequently  called  azo  compounds. 

.CO2C2H5 
C6H6  —  N=NOH  +  CH'  = 

XC02C2H6 
OH  H 
/      / 
C6H6— NH— N  — C— CO2CQH6— 

C02C2H5 

xeotc,H. 

C6H6— NH— N=C  (  +  H20. 

XC02C2H6 

Hydrazone  of  mesoxalic  acid. 
On  the  supposition  that  the  structure  was  represented 

XC02C2H6 
by  the  formula  C6H5— N=N— CH(  ,  this  was 

XC02C2HB 
called  benzeneazomalonic  ester,  a  name  still  used. 

Hydrazides  are  formed  by  the  condensation  of  hydra  - 
zines,  with  bodies  containing  hydroxyl,  the  condensa- 
tion taking  place  readily  only  when  the  hydroxyl  is 
more  or  less  acid  in  its  properties. 

R— NH— NH2  +  RCOOH  = 

R— NH— NH>C=O+  H2O. 
R 

The  name  is  given  from  the  analogy  with  amides. 
Osazones  are  formed  by  the  action  of  an  excess  of 

CHOH 
phenyl  hydrazine  on  bodies  containing  the  group   | 

CO 


NITROGEN   COMPOUNDS.  153 

A  part  of  the  phenyl  hydrazine  combines  at  once  to  form 
a  hydrazone,  a  second  part  oxidizes  the  alcoholic  group 
to  a  ketonic  or  aldehyde  group,  and  the  latter  reacts 
with  more  of  the  hydrazine,  giving  finally  the  group, 

C=N— NHC6H5 

|  .     The  osazones  have  been  of  especial 

C=N— NHC6H6 

importance  in  the  study  of  sugars. 


56.  Preparation  of  a  Hydrazo  Compound. — Hydrazo- 
benzene,  C6H6— NH— NH— CeH6. 

Literature — Hofmann  :  Jsb.  d.  Chem.,  1863,  424;  Alexejew  : 
Ztschr.  Chem.,  1867,  33 ;  1868,  497 ;  B.  Krdmann :  Ztschr. 
angew.  Chem.,  1893,  163. 

30  grams  nitrobenzene. 

200  cc.  alcohol. 

40  cc.  sodium  hydroxide  (3  cc.=  i  gram). 

45  grams  zinc  dust. 

Put  in  a  500  cc.  flask  200  cc.  of  alcohol,  30  grams  of 
nitrobenzene,  and  40  cc.  of  a  solution  of  caustic  soda  (3 
cc.=  i  gram).  Heat  on  a  water-bath  to  about  75°,  put- 
ting in  the  mouth  of  the  flask  a  cork  bearing  a  tube  to 
act  as  an  air  condenser.  Add  a  small  amount  of  zinc 
dust,  shake  and  add  more,  in  small  portions,  till  the 
reaction  begins.  If  the  action  becomes  violent,  check  it 
by  dipping  the  flask  in  cold  water.  Continue  the  warm- 
ing and  addition  of  zinc  dust  till  the  solution  becomes 
nearly  colorless.  Filter  hot  on  a  plate,  cool  quickly, 


154  ORGANIC   CHEMISTRY. 

filter  off  the  hydrazobenzene  as  rapidly  as  possible,  wash 
with  a  little  alcohol,  transfer  it  to  a  flask,  and  add  at 
once  some  alcohol  containing  a  little  ammonium  sul- 
phide to  prevent  oxidation.  Boil  the  residue  of  zinc 
dust  with  the  mother  liquors,  filter  and  separate  the  hy- 
drazobenzene as  before,  and  repeat  a  third  time.  Then 
recrystallize  the  whole  from  hot  alcohol  containing  am- 
monium sulphide,  working  as  rapidly  as  possible,  to 
prevent  oxidation,  and  finally  dry  the  product  in  a 
vacuum  desiccator,  over  sulphuric  acid.  In  recrystal- 
lizing,  water  may  be  added  to  the  hot,  filtered  alcoholic 
solution  till  it  begins  to  be  turbid,  to  cause  the  more 
complete  separation  of  the  hydrazobenzene,  and  the 
product  may  be  washed  with  dilute,  instead  of  pure  alco- 
hol. It  may  also  be  crystallized  from  ligroin.  Yield 
19  to  20  grams. 

Hydrazobenzene  crystallizes  in  colorless  leaflets, 
which  melt  at  131°.  It  is  easily  soluble  in  alcohol,  and 
ether,  almost  insoluble  in  water.  It  is  very  easily  con- 
verted into  azobenzene,  even  by  the  oxygen  of  the  air.  By 
warming  with  hydrochloric  acid,  it  is  converted  into 
benzidine,  NH2— C6H4— C6H4— NH2.  It  is  decomposed 
by  htat  into  azobenzene  and  aniline. 

57.  Preparation  of  an  Azo  Compound. — Azobenzene, 

C6H6— N=N— C6H5. 

Literature. — Mitscherlich :  Ann.  Chem.  (Liebig),  12,  311; 
Zinin:  J.  prakt.  Chem.  36,  93,  (1845};  Claus:  Ber.  d.  chem.  Ges., 
8,  37 ;  Griess :  Ibid,  9,  132;  Frankland  and  Louis  :  J.  Chem.  Soc., 
37,  560,  (1880*)  ;  Spiegel :  Ber.  d.  chem.  Ges.,  18,  1481  ;  Mills  :  J. 
Chem.  Soc.,  65,  51,  (1894). 


NITROGEN   COMPOUNDS.  155 

10  grams  hydrazobenzene. 

170  cc.  alcohol. 

i  cc.  sodium  hydroxide  (3  cc.  =  i  gram). 

Put  in  a  300  cc.  flask  10  grams  of  hydrazobenzene, 
170  cc.  of  alcohol,  and  i  cc.  of  a  solution  of  caustic  soda. 
Close  the  flask  with  a  stopper  bearing  an  upright  con- 
denser, and  a  glass  tube  leading  nearly  to  the  bottom  of 
the  flask.  Heat  on  a  water-bath  and  draw  or  force 
through  the  solution  a  slow  current  of  air  for  three  to 
four  hours.  Filter,  if  necessary,  distil  off  most  of  the 
alcohol  and  allow  the  azo-benzene  to  crystallize  after 
adding  a  little  water.  Yield  7  to  8  grams. 

Azobenzene  crystallizes  in  red  plates,  which  melt  at 
68°.  It  boils  without  decomposition  at  295°.  It  is  sol- 
uble in  12  parts  of  alcohol  at  16°. 

58.  Preparation  of  an  Amino-azo  Compound  through 
the  Diazoamino  Compound.  — /-Aminoazobenzene, 

CH   ^N^N-CeH,  (i). 
M^^HH,  (4). 

Literature.— Griess  :  Ann.  Chem.  (lyiebig),  121,  258;  Staedel 
and  Bauer.;  Ber.  d.  chem.  Ges.,  19,  1952  ;  Niementowski  and 
Roszkowski :  Ztschr.  phys.  Chem.,  22,  145. 

50  cc.  aniline. 

60  cc.  concentrated  hydrochloric  acid. 

13  grams  aniline  chloride. 

200  cc.  water. 

3.5  grams  sodium  nitrite. 

17.5  cc.  water. 

10  grams  crystallized  sodium  acetate. 


156  ORGANIC   CHEMISTRY. 

5  grams  diazoaminobenzene. 

15  grams  aniline. 

3  grams  aniline  chloride. 

Prepare  some  aniline  chloride  by  dissolving  50  cc.  of 
aniline  in  60  cc.  of  concentrated  hydrochloric  acid,  cool- 
ing thoroughly,  filtering  with  a  plate  on  a  hardened  fil- 
ter, and  drying  on  the  water- bath. 

Dissolve  13  grams  of  the  aniline  chloride  in  200  cc.  of 
water,  bring  the  temperature  to  25°,  and  add,  with  stir- 
ring, 3.5  grams  of  sodium  nitrite,  dissolved  in  17.5  cc. 
of  water.  Keep  the  temperature  at  27°-3O°  by  cooling, 
if  necessary.  Add,  at  once,  a  previously  prepared  solu- 
tion of  10  grams  of  crystallized  sodium  acetate,  stir 
thoroughly  and  allow  the  whole  to  stand  for  15  minutes. 
Filter  off  the  diazoaminobenzene,  wash  and  dry  in  vacuo 
over  sulphuric  acid.  The  yield  is  9  to  10  grams.  The  body 
may  be  crystallized  from  gasoline,  or  ligroin,  if  desired. 

Dissolve  5  grams  of  the  dry  diazoaminobenzene  in  15  cc. 
of  aniline,  in  a  small  flask,  add  3  grams  of  dry,  powdered 
aniline  chloride,  warm  in  a  water-bath  at  40°,  for  an 
hour,  and  allow  the  mass  to  stand  for  a  day,  or  until  the 
solution  no  longer  evolves  nitrogen,  when  a  small  portion 
is  warmed  with  alcohol  and  hydrochloric  acid.  Add  40 
cc.  of  hydrochloric  acid  (sp.  gr.  i.io),  cool,  filter,  and 
wash  with  dilute  hydrochloric  acid.  Dissolve  the  chlo- 
ride of  the  aminoazobenzene  in  about  500  cc.  of  hot 
water,  adding  enough  hydrochloric  acid  to  prevent  dis- 
sociation, but  not  more.  Filter,  if  necessary,  and  add 
20  to  25  cc.  of  concentrated  hydrochloric  acid.  On  cool- 
ing, the  chloride  will  separate  almost  completely  in  crys- 


NITROGEN    COMPOUNDS. 


157 


talline   form.     Filter,  wash  with  dilute  acid,   and  dry. 

If  the  free  amiuoazobenzene  is  desired,  it  can  be  ob- 
tained by  warming  the  chloride  with  twice  its  weight  of 
alcohol,  and  adding  concentrated  ammonia  till  it  dis- 
solves. On  further  addition  of  water,  the  base  separates 
in  yellow  leaflets,  which  may  be  recrystallized  from  ben- 
zene. Yield  of  the  chloride  about  4^  grams. 

/-Aminoazobenzene  crystallizes  in  orange-yellow, 
rhombic  prisms,  which  melt  at  127°,  and  boil  without  de- 
composition at  360°.  It  is  almost  insoluble  in  water, 
easily  soluble  in  alcohol  and  ether.  It  is  reduced  by  tin 
and  hydrochloric  acid  to  aniline  and  paraphenylenedi- 
amine.  The  chloride  is  dissociated  by  water.  It  is 
known  as  aniline  yellow,  and  in  slightly  acid  solution 
colors  wool  and  silk  intensely  yellow. 

Diazoaminobenzene  melts  at  98°,  and  is  slightly  explo- 
sive. 

59.  Preparation  of  an  Azo  Compound  by  the  Combi- 
nation of  a  Diazo  Compound  with  an  Amine.— 

benzene-azo-<*-naphthylamine, 

SO3H  NHa 


•N  =  N- 


(4)  -Sulphobenzene-azo-  (4)  -amino-  ( i )  -naphthalene. 


158  ORGANIC   CHEMISTRY. 

Literature. — Griess  :  Ber.  d.  chem.  Ges.,  12,  427. 

5  grams  sulphanilic  acid. 

10  cc.  sodium  hydroxide  (10  per  cent.). 
200  cc.  water. 

10  cc.  hydrochloric  acid  (sp.gr.   i.i). 
1.7  grams  sodium  nitrite. 
8.5  cc.  water. 

3.5  grams  tf-naphthylamine. 

6  cc.  hydrochloric  acid  (sp.  gr.  i.i). 
200  cc.  water. 

Dissolve  5  grams  of  sulphanilic  acid  in  10  cc.  of 
sodium  hydroxide  and  20  cc.  of  water,  by  warming  in  a 
flask.  Cool,  dilute  to  about  200  cc.,  and  add  1.7  grams 
of  sodium  nitrite,  dissolved  in  8.5  cc.  of  water.  Dissolve 
3.5  grams  of  or-naphtylamine  in  6  cc.  of  hydrochloric 
acid  and  200  cc.  of  hot  water.  Cool,  and  add  the  solu- 
tion of  paradiazosulphobenzene.  Mix  thoroughly  by 
pouring  from  one  beaker  to  another  and  back  several 
times.  Allow  to  stand  for  several  hours,  then  heat  on 
the  water-bath,  or  over  the  free  flame,  till  the  precipitate 
becomes  crystalline,  and  much  less  voluminous.  Filter 
hot,  and  wash. 

«-Naphthylamine-azobenzene-/-sulphonic  acid  crys- 
tallizes in  microscopic  needles  of  a  dark  violet  color.  It  is 
almost  insoluble,  even  in  boiling  water,  and  is  also  very 
difficultly  soluble  in  alcohol.  The  dilute  solutions  are  of 
a  bright  red  or  pink  color  and,  since  the  body  is  formed 
quantitatively  when  nitrous  acid  acts  on  an  excess  of  an 
acid  solution  containing  sulphanilic  acid  and  <*-naphthyl- 


NITROGEN    COMPOUNDS.  159 

amine,  it  is  often  used  for  the  determination  of  nitrites 
in  potable  waters. 

Since  the  body  is  a  sulphonic  acid,  it  dissolves  to  clear 
orange-red  solutions  in  very  dilute  solutions  of  caustic 
soda,  or  ammonia,  but  the  addition  of  more  sodium  hy- 
droxide to  such  solutions,  even  if  quite  dilute,  will  cause 
the  precipitation  of  the  red,  crystalline,  sodium  salt, 
C^JH.SO.Nn. 

60.  Preparation  of  a  Salt  of  a  Diazo  Compound. — 
Diazobenzene  chloride,  C6HB — N=N. 

Cl 

Literature. — Griess  :  Ann.  Chem.  (Liebig),  113,  201  ;  117,  i  ; 
121,  257;  137,  39;  Ber.  d.  chem.  Ges.,  24,  R.,  10(57;  V.  Meyer 
and  Ambiihl :  Ibid,  8,  1073 ;  Knoevenagel :  Ibid,  23,  2994 ; 
Hausser  and  Miiller :  Bull.  Soc.  Chim.  [3],  9,  353,  (/£pj). 

2  grams  aniline  chloride. 

8  cc.  alcohol. 

2  cc.  (1.8  grams)  amyl  nitrite,  or 

1.3  cc.  (1.23  grams)  ethyl  nitrite. 

Dissolve  2  grams  of  aniline  chloride  in  8  cc.  of  abso- 
lute alcohol  in  a  test-tube.  Cool  with  ice  water,  add  a 
drop  of  concentrated  hydrochloric  acid,  and  then  very 
slowly,  with  cooling  and  stirring,  2  cc.  of  amyl  nitrite, 
or  1.3  cc.  of  ethyl  nitrite.1  Allow  to  stand  in  ice-water 

1  Ethyl  nitrite  may  be  prepared  as  follows  :  Prepare  a  solution  of  10 
grams  of  sodium  nitrite  in  50  cc.  of  water  and  5  cc.  of  alcohol,  and  a  second  so- 
lution of  5  cc.  of  concentrated  sulphuric  acid,  50  cc.  of  water  and  5  cc.  of  alco- 
hol. Cool  each  to  oe,  and  add  the  acid  solution  to  the  nitrite  solution,  with  a 
pipette,  which  is  inserted  beneath  the  surface  of  the  liquid,  cooling  thor- 
oughly. After  a  few  minutes,  separate  the  ethyl  nitrite,  which  rises  to  the 
top  of  the  liquid,  using  a  cold separatory  funnel.  Keep  the  nitrite  in  a  tube, 


l6o  ORGANIC   CHEMISTRY. 

for  a  short  time,  and  then  filter  off  the  diazobenzene 
chloride  and  wash  it  with  a  very  little  alcohol,  contain- 
ing a  little  hydrochloric  acid,  and  with  ether. 

Separate  into  several  portions  and  dry  on  filter-paper, 
in  the  air.  On  account  of  the  explosive  character,  the 
portions  dried  should  not  exceed  0.1-0.2  gram  each. 

Small  portions  may  be  warmed  with  water,  alcohol,  or 
concentrated  hydrochloric  acid,  to  illustrate  the  decom- 
positions of  the  body,  but  for  most  purposes  of  synthesis, 
the  free  diazo  compounds,  or  salts,  are  not  prepared. 
See  pp.  42,  114,  124,  and  168. 

61.  Preparation  of  a  Hydrazine. — Phenyl  hydrazine, 
C6H6NHNH2. 

Literature. — E.  Fisher  :  Ann.  Chem.  (Liebig),  190,  67  ;  Ber.  d. 
chem.  Ges.,  17,  572  ;  V.  Meyer,  u.  L,ecco  :  Ibid,  16,  2976  ;  Reych- 
ler  :  Ibid,  20,  2463  ;  Ibid,  26,  19  ;  Altschul :  Ibid,  25,  1849. 

1 8. 6  grams  aniline. 

1 60  cc.  hydrochloric  acid  (sp.  gr.   1.19). 

14  grams  sodium  nitrite. 

70  cc.  water. 

50  grams  tin. 

150  cc.  hydrochloric  acid  (sp.  gr.  1.19). 

40  cc.  sodium  hydroxide  (3  cc.=  i  gram), 

Prepare  a  solution  of  stannous  chloride  by  dissolving 
50  grams  of  feathered  tin  in  150  cc.  of  concentrated  hy- 

surrounded  with  ice.  It  boils  at  17°.  If  larger  quantities  of  the  nitrite  are 
desired,  the  solutions  may  be  prepared  in  the  proportions  given,  and  the  ni- 
trite solution  put  in  a  flask  or  distilling  bulb,  connected  with  a  condenser, 
fed  with  ice-water.  The  solutions  should  be  at  20 "-25°.  On  running  the  acid 
solution  in  slowly,  the  ethyl  nitrite  will  distil  over,  and  may  be  collected  in 
a  receiver,  surrounded  with  ice.  (Wallach  and  Otto :  Ann  Chem.  (lyiebig), 
253,  251.) 


NITROGEN    COMPOUNDS.  l6l 

drochloric  acid,  or  by  dissolving  120  grams  of  crystal- 
lized stannous  chloride  in  100  cc.  of  concentrated  hydro- 
chloric acid.  Add  18.6  grams  of  aniline  (i  mol.)  to  100 
cc.  of  concentrated  hydrochloric  acid,  stirring  vigorously. 
Set  the  beaker  in  ice-water,  or  a  freezing  mixture, 
and  when  the  temperature  has  fallen  nearly  to  o°,  add 
150  grams  of  ice,  and  then,  from  a  drop  funnel,  drawn 
to  a  narrow  tube  at  the  end,  or  having  a  narrow 
tube  attached,  and  dipping  nearly  to  the  bottom  of  the 
solution,  add  slowly  and  with  constant  stirring,  a  cold 
solution  of  14  grams  (i  mol.)  of  sodium  nitrite  in  70  cc. 
of  water.  The  temperature  should  not  rise  above  5°. 
When  all  has  been  added,  the  solution,  after  standing 
two  minutes,  should  react  for  nitrous  acid,  when  a  drop 
is  diluted  and  tested  with  starch  iodide  paper.  If  it  does 
not,  a  little  more  sodium  nitrite  must  be  added,  using 
the  least  possible  excess.  As  soon  as  possible,  add 
slowly,  with  stirring,  the  solution  of  stannous  chloride, 
which  must,  meanwhile,  have  been  cooled  to  o°,  or  be- 
low. Add,  if  necessary,  more  ice,  to  keep  the  tempera- 
ture below  10°  during  the  addition  of  the  stannous  chlo- 
ride. Stir  very  thoroughly,  and  allow  to  stand  for  an 
hour.  Filter  off  the  chloride  of  the  phenyl  hydrazine, 
which  separates,  suck  and  press  it  as  free  as  possible 
from  the  mother  liquors,  and  wash  once  with  a  small 
amount  of  dilute  hydrochloric  acid.  Evaporate  the  fil- 
trate to  about  150  cc.,  best  in  a  large  beaker  heated  over 
a  free  flame  on  wire  gauze.  Cool,  and  separate  the  chlo- 
ride of  the  phenyl  hydrazine,  which  crystallizes,  as  be- 
fore. Dissolve  the  chloride  in  a  small  amount  of  warm 


162  ORGANIC    CHEMISTRY. 

water,  add  an  excess  of  a  strong  solution  of  sodium  hy- 
droxide, cool,  collect  the  phenyl  hydrazine  with  a  little 
ether,  separate,  distil  off  the  ether,  dry  by  allowing  to 
stand  in  vacua  over  sulphuric  acid,  or  dry  with  fused 
caustic  potash,  pour  off  and  distil,  best  under  diminished 
pressure.  Some  ammonia  is  formed  during  the  distilla- 
tion, which  may  be  removed  by  allowing  the  product  to 
stand  over  sulphuric  acid.  The  phenyl  hydrazine  may 
be  further  purified  by  a  second  distillation,  or  by  allow- 
ing it  to  solidify  at  a  low  temperature,  and  pouring  off 
the  liquid  portion.  Yield,  about  18  grams. 

Phenyl  hydrazine  boils  at  242°,  and  solidifies  at  a  low 
temperature,  melting  at  19°.  Its  specific  gravity  is 
1.097,  at  23°.  It  is  a  violent  poison.  On  adding  a  so- 
lution of  phenyl  hydrazine  acetate  to  a  hot  solution  of 
copper  sulphate,  it  is  oxidized  with  the  formation  of 
benzene.  With  aldehydes,  ketones,  and  sugars,  phenyl 
hydrazine  gives  characteristic  condensation  products. 
See  62,  below,  and  74,  p.  190. 

62.  Preparation  of  an  Osazone.  —  Glucosazone, 
CH2OH 

CHOH 

CHOH 

(Dextrosazone,  levulosazone). 
CHOH 

I 
C=N— NHC6H6 

CH=N— NHCJL 


NITROGEN   COMPOUNDS.  163 

t 

Literature. — E.  Fischer:  Ber.  d.  chem.  Ges.,  17,  580;  Jaksch : 
Ztschr.  anal.  Chem.,  24,  478;  Beythien  :  Ann.  Chem.  (L,iebig), 
255,  218. 

2  grams  glucose. 

4  grams  phenyl  hydrazine. 

10  cc.  acetic  acid  (30  per  cent.). 

50  cc.  water. 

Dissolve  2  grams  of  glucose  in  50  cc.  of  water,  add  a 
solution  of  4  grams  of  phenyl  hydrazine  in  10  cc.  of  acetic 
acid,  and  heat  on  a  water-bath  for  two  hours.  Cool,  fil- 
ter off  the  glucosazone  and  recrystallize  it  from  80  per 
cent,  alcohol. 

Glucosazone  melts,  when  heated  quickly,  at  206°,  and 
crystallizes  in  characteristic  yellow  needles.  With  di- 
phenyl  hydrazine  glucose  gives  an  even  more  character- 
istic hydrazone.  (Stahel :  Ann.  Chem.  (L,iebig),  258, 
244.) 


VII. 


Alcohols  and  Phenols. 

Alcohols  are  prepared  from  the  halogen  derivatives  of 
hydrocarbons,  by  treatment  with  water,  potassium  car- 
bonate and  water,  silver  oxide  and  water,  or  potassium 
or  silver  acetate,  followed  by  saponification  of  the  acetic 
ester  of  the  alcohol,  which  is  formed.  The  iodides  re- 
act more  readily  than  other  halogen  derivatives,  but 
bromides  are  often  used. 

2RI  +  K2C03  +  H20  =  2ROH  +  2KI  +  CO3. 
RI  +  AgC3H8Oa  =  R  —  O  —  C2H30  +  Agl . 
RO  —  C3H3O  +  KOH  =  R  —  OH  +  KC2H3Oa. 

From  unsaturated  hydrocarbons  alcohols  can  be  ob- 
tained by  dissolving  them  in  concentrated  sulphuric 
acid,  diluting,  and  distilling.  The  method  gives  second- 
ary and  tertiary  alcohols  in  cases  where  their  formation 
is  possible. 

Cn  H2n  +  H2S04  =  Cn  H2n+I  HS04 . 
Cn  Han+I  HSO4  +  H2O  =  Cn  H2n+I  OH  +  H2SO4. 

Aldehydes  may  be  reduced  to  primary  alcohols,  and 
ketones  to  secondary  alcohols.  The  reducing  agents 
most  often  used  are  sodium  amalgam  in  aqueous  solu- 
tions, sodium  in  alcoholic  or  moist  ethereal  solutions,  or 
zinc  dust  and  glacial  acetic  acid.  The  last  method  gives 
an  acetate  which  requires  saponification. 

Amines  may  be  converted  into  alcohols  by  the  action 


ALCOHOLS   AND   PHENOLS.  165 

of  nitrous  acid  in  aqueous  solutions.  In  the  aromatic 
series  a  diazo  compound  is  first  formed.  In  the  aliphatic 
series,  and  especially  in  cyclic  compounds,  unsaturated 
hydrocarbons  are  also  formed,  and  interfere  seriously 
with  the  yield. 

RNHa  +  HNOa  =  ROH  +  Na  +  HaO. 

R<NH,  +  HNO»  =  R"  +  N'  +  2H'°' 

In  the  aromatic  series  sulphonic  acids,  and  in 
many  cases  halogen  derivatives,  may  be  converted  into 
phenols  by  fusion  with  potassium  hydroxide.  The  re- 
action is  accompanied,  in  some  cases,  by  a  rearrange- 
ment, which  interferes  with  its  reliability  for  the  determi- 
nation of  structure. 

RSOaOH  +  2KOH  =  ROH  +  KaSO3  +  HaO. 

Glycols,  that  is,  alcohols  having  two  hydroxyl  groups 
combined  with  adjacent  carbon  atoms,  may  be  prepared, 
in  some  cases,  by  oxidizing  olefines  with  a  cold  solution 
of  potassium  permanganate. 

R— CH  R— CHOH 

||     +  0  +  HaO  =         | 
R— CH  R— CHOH 

This  reaction  is  of  greater  importance  for  the  prepar- 
ation of  dihydroxy  acids  than  for  the  preparation  of 
glycols,  however.  (See  Fittig :  Ber.  d.  chem.  Ges.,27, 
2670.) 

Many  aromatic  aldehydes,  on  treatment  with  potas- 
sium hydroxide  and  water,  are  converted  into  a  mixture 


1  66  ORGANIC   CHEMISTRY. 

of  the  potassium  salt  of  the  corresponding  acid,  and  the 
corresponding  alcohol. 

2RCHO  +  KOH  =  RCH2OH  + 


63.  Preparation  of  a  Diacid  Alcohol  from  a  Halogen 
Derivative  ot  a  Hydrocarbon.  —  Bthylene  glycol, 
CH2OH 

|  (Ethanediol). 

CH2OH 

Literature.  —  Wurtz  :  Compt.  Rend.,  43,  199,  (y#5<5)  ;  Jeltekow  : 
Ber.  d.  chem.  Ges.,  6,  558;  Niederist  ;  Ann.  Chem.  (Liebig), 
186,393;  196,  354;  Erlenmeyer  :  Ibid,  192,  355;  Wagner:  Ber. 
d.  chem.  Ges.,  21,  1234,  3346;  Haworth  and  W.  H.  Perkin,  Jr.  : 
J.  Chem.  Soc.,  69,  175. 

18.8  grams  ethylene  bromide  (three  times  repeated)  . 

13.8  grams  potassium  carbonate  (three  times  repeated)  . 

100  cc.  water. 

Put  in  a  200  cc.  flask  18.8  grams  of  ethylene  bromide, 
13.8  grams  of  dry  potassium  carbonate,  and  100  cc.  of 
water.  Connect  with  a  reversed  condenser,  and  boil 
gently  till  the  ethylene  bromide  disappears,  usually 
eight  to  ten  hours.  Add  the  same  amounts  of  ethylene 
bromide  and  potassium  carbonate,  and  boil  as  before. 
Repeat  a  third  time.  The  addition  of  a  few  small 
pieces  of  wood  will  help  to  prevent  bumping.  Some 
vinyl  bromide,  CH2—  -CHBr,  escapes  during  the  boiling, 
and  can,  if  desired,  be  converted  into  tribromethane,  by 
leading  through  a  bottle  containing  bromine.  If  large 
amounts  of  glycol  are  desired,  the  addition  of  ethylene 
bromide  and  potassium  carbonate  may  be  repeated  six 


ALCOHOLS   AND   PHENOLS.  167 

times  instead  of  three,  but  in  that  case  it  is  necessary  to 
filter  off  the  potassium  bromide,  which  separates  on 
cooling  the  solution  after  each  boiling. 
'  Concentrate  the  solution  in  vacuo  over  sulphuric  acid, 
pour  off  from  the  potassium  bromide  which  separates,  wash 
the  latter  with  a  little  absolute  alcohol,  and  submit  to 
fractional  distillation.  Or  the  aqueous  solution  may  be 
distilled  at  once,  best  under  diminished  pressure,  and 
the  distillate  used  in  a  new  preparation,  since  the  glycol 
is  quite  volatile  with  water  vapor. 

Ethylene  glycol  is  a  colorless  liquid,  with  a  sweet 
taste.  It  boils  at  197°,  and  solidifies  in  a  freezing  mix- 
ture. It  is  miscible  in  all  proportions  with  water  and 
alcohol,  but  not  with  ether.  Platinum  black  oxidizes  it 

CO2H 

to  glycollic  acid,   |  . 

CH2OH 

64.  Preparation  of  an  Alcohol  by  the  Reduction  of  a 

Ketone.— Phenyl  methyl carbinol,  p6J?5>CHOH,   phen- 

CH3 

ethylol  (i). 

Literature.— Radziszewski :  Ber.  d.  chem.  Ges.,7»  141  ;Berthe- 
lot:  Ztschr.  Chem.,  1868,  589;  Emmerling,  Engler :  Ber.  d. 
Ges.,  4,  147  ;  6,  1006. 

10  grams  acetophenone. 

100  cc.  ether. 

30  cc.  water. 

8-10  grams  sodium. 

Put  in  a  200  cc,  flask  10  grams  of  acetophenone,1  30  cc. 

1  This  may  be  prepared  exactly  as  directed  for  benzophenone  (71,  p.  184), 


1  68  ORGANIC    CHEMISTRY. 

of  water,  and  100  cc.  of  ether.  Add  sodium  in  small 
pieces,  shaking  gently,  and  cooling  the  flask  with  water, 
till  the  ethereal  solution  no  longer  gives  a  turbidity 
when  a  drop  of  it  is  put  in  a  test-tube  with  a  dilute  solu- 
tion of  phenyl  hydrazine  acetate  (see  75,  p.  191).  8-10 
grams  of  sodium  will  usually  be  required.  Toward  the 
close  more  water  may  be  added  if  the  solution  of  the 
sodium  takes  place  too  slowly.  Separate  the  ethereal 
solution,  distil  off  the  ether,  dry  the  residue  in  vacua 
over  sulphuric  acid,  or  by  heating  on  a  water-bath  under 
diminished  pressure  with  a  capillary  (pp.  36  and  46),  and 
distil.  Yield  6  to  7  grams.  The  yield  is  diminished  by 

the  formation  of  the  pinacone,  9?5*>C  —  C 


OH  OH 

Phenyl-methyl-carbinol  boils  at  2O2°-2O4°,  and  has  a 
specific  gravity  of  1.013. 

65.  Preparation  of  a  Phenol  by  the  Decomposition  of 
an  Amine  through  the  Diazo  Compound.  —  Paracresol, 

C«H<<OH3   (4)!     (AMethyl  phenol.) 

Literature.  —  Stadeler  :  Ann.  Chem.  (Liebig),  77,  18;  Salkow- 
ski  :  Ber.  d.  chem.  Ges.,  12,  1440;  Griess  :  Jsb.  d.  chem.,  1866, 
458;  Kb'rner  :  Ztschr.  Chem.,  1868,  326;  Wurtz  :  Ann.  Chem. 
(Liebig),  144.  139;  156,  258;  Oudemans  :  Ibid,  170,259;  South- 
worth  :  Ibid,  168,  271  ;  Pinette,  Ibid,  243,  43. 

using  12  grams  of  acetyl  chloride  in  place  of  20  grams  of  benzoyl  chloride. 
The  yield  is  about  12  grams  of  acetophenone.  It  melts  at  20.5°  and  boils  at 
202°.  Acetophenone  may  also  be  prepared  by  bringing  together  equivalent 
amounts  of  benzoic  acid  and  acetic  acid  with  some  water,  and  a  Itttle  more 
than  the  equivalent  amount  of  calcium  carbonate,  evaporating  to  dryness  and 
distilling  the  residue  from  a  retort  or  flask. 


ALCOHOLS  AND   PHENOLS.  169 

20  grams  paratoluidine. 

600  cc.  water. 

20  cc.  concentrated  sulphuric  acid. 

15  grams  sodium  nitrite. 
75  cc.  water. 
2  grams  urea. 

30  cc.  sodium  hydroxide  (3cc.=  i  gram). 
10  cc.  concentrated  sulphuric  acid. 
30  cc.  water. 

In  a  one  liter  flask  put  20  grams  of  paratoluidine,  600 
cc.  of  water,  and  20  cc.  of  concentrated  sulphuric  acid. 
Heat  till  dissolved.  Cool  to  20°  or  below,  and  add 
slowly,  with  shaking,  a  solution  of  15  grams  of  sodium 
nitrite,  in  75  cc.  of  water,  keeping  the  temperature  be- 
low 20°.  Allow  to  stand  for  a  short  time,  add  2  grams 
of  urea,  connect  with  a  condenser,  and  distil  over  the 
paracresol  with  water  vapor  (p.  14),  distilling  till  the 
distillate  gives  no  turbidity  with  bromine  water.  Add 
to  the  distillate  30  cc.  of  a  strong  solution  of  caustic  soda 
and  a  little  bone-black,  and  concentrate  rapidly  to  about 
75  cc.  by  boiling  in  a  large  lip  beaker,  covered  with  a 
watch-glass,  to  prevent  oxidation.  Filter  into  a  beaker 
containing  10  cc.  of  concentrated  sulphuric  acid  diluted 
with  30  cc.  of  water.  Cool,  and  extract  the  cresol  with 
ether,  extracting  three  or  four  times.  Dry  the  solution 
for  a  few  minutes  with  calcium  chloride,  pour  off,  distil 
the  ether  from  a  water-bath,  dry  the  residue  in  vacua 
over  sulphuric  acid,  and  distil.  Yield  15  to  16  grams. 

The   urea  is  added  to  destroy  the  excess  of  nitrous 


170  ORGANIC   CHEMISTRY. 

acid,  which  would  interfere  seriously  with  the  yield,  if 
allowed  to  remain. 

Paracresol  crystallizes  in  prisms  which  melt  at  36°. 
It  boils  at  201.8°,  and  has  a  specific  gravity  of  0.9962  at 
65.6°.  It  is  slightly  soluble  in  water.  Its  aqueous  solu- 
tion gives  a  blue  color  with  ferric  chloride.  There  is 
usually  difficulty  in  getting  the  cresol  to  solidify.  In 
that  case  a  drop  may  be  put  in  a  dry  test-tube,  placed  in 
some  ether  in  a  small  beaker.  By  blowing  air  through 
the  ether  the  temperature  can  be  lowered  to  o°  or  below. 
When  a  crystal  of  cresol  obtained  in  this  way  is  added 
to  the  rest,  the  whole  will  solidify. 

66.  Preparation  of  a  Dihydroxy  Compound  from 
an  Amine  through  the  Quinone.  —  Hydroquinone, 

C.H4<QH  (4)!     0-4-Phendiol). 

Literature.— Workresenski :  Ann.  Chem.  (Liebig),  27,  268; 
Wohler  :  Ibid,  45»  354  ;  Nietzki :  Idid,  215,  127  ;  Ber.  d.  chem. 
Ges.,  19,  1467;  Schniter  :  Ibid,  20,  2283;  Wohler:  Ann.  Chem. 
(L,iebig),  51,  152;  Strecker  :  Ibid,  107,  229;  Salkowski :  Ber.  d. 
chem.  Ges.,  7,  1010;  Hlasiwetz :  Ann.  Chem.  (L,iebig),  175,  67; 
Weselski  and  Schuler  :  Ber.  d.  chem.  Ges.,  9,  1160  ;  Richter  :  J. 
prakt.  Chem.,  [2],  20,  207,  (/£/p)  ;  Herrmann  :  Ann.  Chem. 
(Liebig),  an,  336;  Ekstrand :  Ber.  d.  chem.  Ges.,  xx,  713; 
Clarke:  Am.  Chem.  J.,  14,  555;  Nef :  Ibid,  12,  483;  Seyda : 
Ber.  d.  chem.  Ges.,  16,  687. 

TO  grams  aniline. 

250  cc.  water. 

80  grams  (44  cc.  concentrated  sulphuric  acid). 

30  grams  sodium  pyrochromate. 

120  cc.  water. 

Sulphur  dioxide. 


ALCOHOLS   AND   PHENOLS. 


Put  in  a  beaker  10  grains  of  aniline,  250  cc.  of  water, 
and  80  grams  (44  cc.)  of  concentrated  sulphuric  acid. 
Put  the  beaker  in  ice-water  or  a  freezing  mixture,  and 
cool  to  5°.  Stir  the  solution  by  means  of  a  turbine  or 
hot  air  motor,  and  drop  in  very  slowly  a  solution  of  10 


Fig.  21. 

grams  of  sodium  pyrochromate  in  40  cc.  of  water.  Allow 
the  solution  to  stand  in  a  cool  place  over  night,  and  then 
add,  with  stirring  and  cooling,  as  before,  20  grams  of 
the  pyrochromate,  dissolved  in  80  cc.  of  water.  The 
temperature  should  not  rise  above  10°  during  the  addi- 
tion of  the  salt.  If  the  sodium  pyrochromate  can  not 
be  had,  very  finely  powdered  potassium  pyrochromate 
may  be  used  instead.  After  five  or  six  hours,  pass  into 


172 


ORGANIC   CHEMISTRY. 


the  solution,  which  now  contains  quinone,  C6H4O2,  a 
rapid  current  of  sulphur  dioxide1  till  the  solution  smells 
very  strongly  of  the  gas.  If  the  odor  of  the  gas  disap- 
pears after  two  hours,  pass  in  more  of  the  gas  and  allow 
the  mixture  to  stand  again.  Extract  the  solution  sev- 
eral times  with  ether  (see  8,  p.  38) ,  distil  off  the  ether,  and 
crystallize  the  hydroquinone  from  water,  using  a  little 
bone-black  to  decolorize  it,  and  a  little  sulphur  dioxide 
to  prevent  oxidation.  Yield  6  to  8  grams. 

Hydroquinone  crystallizes  in  colorless  prisms,  which 
melt  at  169°.  It  is  soluble  in  17  parts  of  water  at  15°. 

67.  Preparation  of  a  Dihydroxyquinone  by  Fusion 
of  a  Sulphonic  Acid  with  Sodium  Hydroxide  and  Po- 
tassium Chlorate. — Alizarin, 

H  OH 


CO 


OH 


CO 


( i .  2- Anthraquinonediol) . 

Literature. -Graebe,  lyiebermann  :  Ann.  Chem.  (Liebig),i6o,  131: 
Liebermann  :  Ber.  d.  chem.  Ges.,  7,  805  ;  A.  G.  Perkin,  Hummel : 
J.  Chem.  Soc.,  63,  1167;  Liebermann,  Graebe:  Ann.  Chem. 
(Liebig),  Supl.,  7,  296;  Ber.  d.  chem.  Ges.,  i,  49,  104,  106  ;  3, 
359 ;  Perkin  :  J.  Chem.  Soc.,  (1876}  ;  Ber.  d.  chem.  Ges.,  9,  281 ; 
Iviebermann,  L,ifschiitz  :  Ber.  d.  chem.  Ges.,  17,  901  ;  L,agod- 
zinski :  Ber.  d.  chem.  Ges.,  28,  1427. 


1  This  is  most  easily  generated  by  dropping  concentrated  sulphuric  acid 
into  a  40  per  cent,  solution  of  acid  sodium  sulphite. 


ALCOHOLS   AND    PHENOLS.  173 

10  grams  anthraquinone. 

25  cc.  fuming  sulphuric  acid  (sp.  gr.  1.875  at  25°). 

200  cc.  water. 

50  grams  salt. 

10  grams  sodium  anthraquinone  sulphonate. 

40  grams  sodium  hydroxide. 

5  grams  water. 

3  grams  potassium  chlorate. 

Put  in  a  small  flask  10  grams  of  anthraquinone,  and  25 
cc.  of  fuming  sulphuric  acid  (containing  10  to  12  per 
cent,  of  the  anhydride;  sp.  gr.  1.875  at  25°).  Cover 
with  a  small  watch-glass,  and  heat  to  2Oo°-23O°  in  an  oil 
bath,  raising  the  temperature  to  this  point  slowly,  for 
about  two  hours,  or  till  a  drop  of  the  solution  separates 
.little  or  no  anthraquinone  on  dilution  with  water. 
Allow  to  cool,  pour  into  200  cc.  of  water,  filter,  if 
necessary,  and  add  50  grams  of  salt,  stir  thoroughly  and 
allow  to  stand  for  some  time,  in  cold  water,  till  the  so- 
dium anthraquinone  sulphonate  separates.  Filter  off, 
press,  and  dry  on  porous  porcelain. 

In  a  nickel  or  iron  crucible  put  40  grams  of  sodium  hy- 
droxide, and  5  cc.  of  water,  and  warm  gently  till  the 
mass  melts,  then  stir  in  a  mixture  of  10  grams  of  the  so- 
dium anthraquinone  sulphonate,  with  3  grams  of  potas- 
sium chlorate.  The  latter  is  for  the  purpose  of  oxidizing 
to  alizarin  the  hydroxyanthraquinone  which  is  formed 
by  fusion  with  the  sodium  hydroxide,  from  the  mono- 
sulphonate.  Heat  gently  and  stir  for  five  to  ten  min- 
utes, and  cool. 


174  ORGANIC   CHEMISTRY. 

The  transformation  may  also  be  effected  with  advantage 
in  an  autoclave,  or  in  an  iron  tube  (Mannesmann 
tube) ,  having  a  cap  screwed  on  the  end  which  is  made 
tight  with  a  lead  washer.  In  that  case  use  40  cc.  of 
water  instead  of  5  cc.,  and  heat  for  20  hours  at  170°. 

Dissolve  the  fused  mass  in  hot  water,  filter,  neutralize 
the  hot  solution  with  hydrochloric  acid  (150  cc.,  sp.gr. 
i.u),  filter  off,  wash,  and  dry  the  precipitated  alizarin. 
The  alizarin  may  be  crystallized  from  alcohol,  glacial 
acetic  acid,  or  nitrobenzene.  It  may  also  be  obtained 
in  beautiful  crystals  by  sublimation.  For  this  purpose 
sink  a  porcelain  crucible,  about  5  cm.  in  diameter,  in  a 
sand-bath  to  its  edge,  cover  it  with  a  round  filter,  place 
on  this  a  funnel  of  the  same  size  as  the  crucible,  with  the 
stem  closed  with  a  rubber  cap,  or  bit  of  rubber  tubing, 
with  a  rod  in  it.  Having  put  the  alizarin  in  the  cruci- 
ble, heat  gently  till  the  crystals  begin  to  appear  in  the 
funnel.  Then  remove  the  flame,  or  lower  it,  and  allow 
the  whole  to  stand  till  the  sublimation  is  complete. 
Yield  2  to  3  grams.  By  use  of  an  autoclave  the  yield  of 
crude  alizarin  is  about  7  grams. 

Alizarin  crystallizes  in  long,  orange-red  prisms,  which 
melt  at  2S^°-2go°.  It  boils  with  some  decomposition  at 
430°,  but  may  be  sublimed  even  at  140°.  It  is  almost 
insoluble  in  cold  water,  easily  soluble  in  alcohol,  and 
ether.  It  dissolves  in  alkalies  to  a  purple  solution.  In 
dyeing  with  it,  an  aluminium  mordant  gives  a  red,  a 
ferric  salt  a  violet,  and  a  chromium  salt  a  reddish 
brown.  By  distillation  with  zinc  dust,  alizarin  is  re- 
duced to  anthracene,  the  reaction  which  first  led  to  a 


ALCOHOLS   AND    PHENOLS.  175 

knowledge  of   its  composition.      (Graebe  and  L/ieber- 
niann  :  Ber.  d.  chein.  Ges.,  i,  49. 

68.  Preparation  of  an  Unsatu  rated  Alcohol. — Allyl 
alcohol,  CH2=CH— CHaOH.  (i.3-propenol). 

Literature. — Berthelot  and  de  Lucca  :  Ann.  Chem.  (Liebig), 
100,  359 ;  Cahours  and  Hofmann  :  Ibid,  102,  285  ;  Aronheim  : 
Ber.  d.  chem.  Ges.,  7,  1381 ;  Tollens,  Henninger :  Ann.  Chem. 
(Liebig),  156,  134,  142;  Tollens:  Ibid,  167,  222;  Romburgh : 
Jsb.  d.  chem.,  1881,  508  ;  Bigot :  Ann.  Chim.  Phys.,  [6],  23,  464. 

200  grams  glycerine. 

50  grams  crystallized  oxalic  acid. 

0.25  gram  ammonium  chloride. 

In  a  300  cc.  distilling  bulb  put  200  grams  of  glycerine, 
50  grams  of  crystallized  oxalic  acid,  and  \  gram  of  am- 
monium chloride,  the  last  being  added  to  decompose 
any  alkali  salts  present,  which  would  interfere  with 
the  reaction.  Insert  a  thermometer,  immersed  in 
the  liquid,  and  connect  with  a  condenser.  Heat  gently 
so  that  the  temperature  rises  slowly.  The  portion  dis- 
tilling below  195°  consists  mainly  of  dilute  formic  acid 
(see  16,  p.  61) ,  and  may  be  converted  into  the  lead  salt  by 
boiling  with  lead  carbonate.  Collect  by  itself  the  por- 
tion coming  over  from  195°  to  240°.  When  the  latter 
temperature  is  reached,  cool,  add  30  grams  of  oxalic 
acid  and  distil  as  before. 

Unite  the  distillates  (i95°-24O°)  and  distil,  collecting 
the  portion  boiling  below  105°.  Add  dry  potassium 
carbonate  till  the  allyl  alcohol  separates  above,  separate 
and  add  10  per  cent,  of  its  weight  of  powdered  caustic 
potash,  and  allow  the  mixture  to  stand  for  some  time, 


176  ORGANIC   CHEMISTRY. 

until  the  odor  of  acrolein  has  disappeared,  separate  and 
distil,  collecting  the  portion  boiling  at9O°-96°.  In  order  to 
remove  the  last  traces  of  water,  it  is  necessary  to  distil 
again,  after  standing  for  some  time,  with  lime  or  barium 
oxide.  Yield  12  to  15  grams. 

Allyl  alcohol  boils  at  96.6°,  and  has  a  specific  gravity 
of  0.8573,  at  15°.  When  dilute  allyl  alcohol  is  treated 
with  bromine  dissolved  in  a  solution  of  potassium  bro- 
mide, the  dibromide,  CH2BrCHBrCH3OH,  is  formed, 
and  the  reaction  may  be  used  for  quantitative  determi- 
nations. 

69.  Preparation  of  an  Alcohol  of  the  Aromatic  Series 
by  Treatment  of  an  Aldehyde  with  Caustic  Potash. 

Benzyl  alcohol,  C6H5CH2OH  (phenmethylol). 

Literature. — Kraut :  Ann.  Chem.  (Ijebig),  152,  129  :  Busse  : 
Ber.  d.  chein.  Ges.,  9,830;  Cannizzaro  :  Ann.  Chem.  (Ljebig), 
88,  129;  96,  246;  Herrmann:  Ibid,  132,  76;  Lauth,  Grimaux  : 
Ibid,  143,  81  ;  Niederist :  Ibid,  196,  353  ;  Kachler  :  Ber.  d.  chem. 
Ges.,  2,  514;  R.  Meyer:  Ibid,  14,  2394;  Graebe  :  Ibid,  8,  1055. 

30  grams  benzaldehyde. 

27  grams  potassium  hydroxide. 

25  cc.  water. 

Dissolve  27  grams  of  caustic  potash  in  25  cc.  of  water, 
add  the  solution  to  30  grams  of  benzaldehyde,  and  shake 
till  an  emulsion  is  formed.  Allow  the  mixture  to  stand 
for  24  hours.  Add  enough  water  to  dissolve  the  potas- 
sium benzoate,  and  extract  with  ether.  Distil  off  the 
ether,  dry  under  diminished  pressure  with  a  capillary 
(see  7,  p.  36),  and  distil  with  an  air  condensing  tube. 
From  the  alkaline  solution  the  benzoic  acid  may  be  pre- 


ALCOHOLS  AND  PHENOLS.  177 

cipitated  and  purified  by  recrystallizing  from  hot  water. 
Yield  14  to  15  grams,  if  the  benzaldehyde  used  is  free 
from  benzoic  acid. 

Benzyl  alcohol  boils  at  204.7°,  and  has  a  specific  grav- 
ity of  1.0507  at  15.4°.  It  dissolves  in  25  parts  of  water 
at  17°.  It  combines  with  calcium  chloride,  and  cannot 
be  dried  by  that  agent. 


VIII. 


Aldehydes,  Ketones  ond  their  Derivatives* 

Aldehydes  are  prepared  by  the  oxidation  of  primary, 
ketones  by  the  oxidation  of  secondary,  alcohols,  the 
oxidizing  agent  being,  usually,  potassium  or  sodium  py- 
rochromate  and  dilute  sulphuric  acid,  at  moderate  tem- 
peratures. Beckmann's  mixture  consisting  of  60  grams 
(i  molecule)  of  potassium  pyrochromate  (or  54  grams  of 
sodium  pyrochromate),  50  grams  (2.5  molecules)  of  con- 
centrated sulphuric  acid,  and  300  cc.  of  water,  is  most 
generally  suitable.  (Am.  Chem.  (Liebig)  250,  325). 

H0. 


Aldehydes  are  prepared  by  distilling  a  mixture  of  a 
calcium  or  barium  salt  of  an  acid,  with  calcium  or 
barium  formate,  ketones  by  distilling  a  calcium  salt  of 
an  acid,  or  a  mixture  of  calcium  or  barium  salts.  Biba- 
sic  acids,  in  which  the  two  carboxyl  groups  are  sepa- 
rated by  four,  five  or  six  carbon  atoms,  give  cyclopenta- 
non,  hexanon,  or  heptanon,  and  their  derivatives  by  the 
same  method.  In  most  cases  it  is  not  necessary  to  pre- 
pare the  calcium  salt,  but  a  mixture  of  the  acid  with 
a  considerable  excess  of  quicklime  may  be  used  instead. 
As  with  most  pyrogenic  reactions,  the  yields  are  consid- 
erably below  the  theoretical,  and  secondary  reactions, 
causing  the  formation  of  alcohols  and  other  products, 
take  place. 


ALDEHYDES,  KETONES,  AND  DERIVATIVES.        179 

In  the  aromatic  series,  aldehydes  may  be  prepared  by 
treating  hydrocarbons  with  chromyl  chloride,  followed 
by  water.  The  hydrocarbon  and  chromyl  chloride  are 
diluted  with  carbon  bisulphide,  and  great  care  must  be 
used  to  avoid  accidents,  (fitard:  Ann.  Chim.  Phys.  [5], 
22,  225  ;  Bornemann  :  Ber.  d.  chem.  Ges.,  17,  1464.) 


2CrO.Cl.= 
R-CH 


Monochlor  derivatives  having  the  group  CHaCl  are 
often  converted  into  aldehydes  by  boiling  with  an  aque- 
ous solution  of  some  nitrate. 

R  —  CH,C1  +  O  =  R  —  C/     +  HC1. 


Ketones  are  prepared  by  the  action  of  chlorides  of 
acids  on  zinc  alky  Is,  or  in  the  aromatic  series,  on  hydro- 
carbons in  the  presence  of  aluminum  chloride. 

.  R  X  OZnR 

RCOCl  +  Zn(     -R—  C—  R 
XR  \C1 

XOZnR 

R  —  C—  R         +  RCOC1  =  2R  —  CO  —  R  +  ZnCla. 
\C1 

or 

XOZnR  OH 

R—  C—  R         +  H,O  =  R—  CO—  R+Zn;        +  RH. 

\C1  XC1 

RH  +  RCOC1  +  A1C1.  =  R  —  CO—  R+HC1  +  A1C1,. 


ISO  ORGANIC    CHEMISTRY. 

Ketones  are  prepared  from  acetacetic  ester  and  similar 
compounds  by  the  "  ketonic  decomposition."  (See 
p.  8). 

In  the  aromatic  series,  aldehydes  may  be  prepared  by 
the  careful  oxidation  of  cinnamic  acid  and  its  deriva- 
tives, in  alkaline  solution,  by  means  of  potassium  per- 
manganate. This  is  in  some  sense  the  reverse  of  the 
preparation  of  cinnamic  acid  from  benzaldehyde. 
R— CH=CH— CO,H-f40  =  R— CHO  +  2CO2+HaO. 
(Einhorn  :  Ber.  d.  chem.  Ges.,  17,  121). 

Quinones  are  usually  prepared  by  the  oxidation  of 
aniline  and  its  homologues,  having  a  hydrogen  atom,  or 
a  hydroxy  or  amino  group  in  the  para  position  to  the 
amino  group.  Potassium  or  sodium  pyrochromate  and 
sulphuric  acid  are  usually  employed.  In  some  cases, 
(e.  g.,  anthracene),  a  hydrocarbon  can  be  oxidized 
directly  to  a  quinone.  The  reaction  in  the  case  of  bodies 
containing  the  amino  group  is  complicated,  and  cannot 
be  expressed  by  a  simple  reaction  (see  66,  p.  170). 

Aldehydes  and  ketones  are  very  reactive  bodies,  pass- 
ing readily  into  alcohols  and  acids  by  reduction,  or  oxi- 
dation, and  condensing  very  easily  with  a  great  variety  of 
other  substances,  which  makes  them  especially  valuable 
for  synthetical  purposes.  The  most  characteristic  con- 
densation products,  and  those  most  often  used  for  pur- 
poses of  identification  and  purification,  because  of  their 
crystalline  character,  are  the  double  compounds  with  acid 
sulphites  of  the  alkali  metals  ;  the  phenyl  hydrazones, 
(E.  Fisher:  Ber.  d.  chem.  Ges.,  17,  572;  21,  958;  22, 
90)  ;  oximes,  (V.  Meyer  and  Janny :  Ber.  d.  chem. 


ALDEHYDES,    KETONES,    AND   DERIVATIVES.       l8l 

Ges.,  15,  1324,  1525);  and  the  semicarbazones,  (Baeyer: 
Ber.  d.  chem.  Ges.,  27,  1918;  Thiele  and  Stange  : 
Ann.  Chem.  (L,iebig),  283,  i  ;  Thiele  and  Heuser  :  Ibid, 
288,311.) 

OH 
NaHSOs  =      >C  —  SO3Na. 


Double  compound  vith 
hydrogen  sodium  sulphite. 

£>CO+C6H6NHNH2  =  ^>C=N—  NHC6HB+H20. 

Phenyl  hydrazone. 

*>CO  +  NH2OH  =  *>C 

Oxime. 
|>CO+  NH2—  NH—  CO—  NH2  = 


>C=N—  NH—  CONH2+H2O. 

Semicarbazoue. 

70.  Preparation  of  an  Aldehyde  by  Oxidation  of  a 
Primary  Alcohol.—  Acetaldehyde,  CH.C^Q  (Etha- 
nol). 

Literature.—  Liebig  :  Ann.  Chem.  (Liebig),  14,  133;  Ritter: 
Ibid,  97,  369;  Stadeler  :  Jsb.  d.  chem.,  1859,  329  ;  J.  prakt. 
Chem.,  76,  54,  (1859);  Bourcart  :  Ztschr.  anal.  Chem.,  29,609; 
Rogers:  J.  prakt.  Chem.,  40,  244,  (1847);  Weidenbusch  :  Ann. 
Chem.  (Liebig),  66,  152;  Ritter:  Ibid,  97,369;  Tollens:  Ber.  d. 
chem.  Ges.,  14,1950;  Orndorff  and  White  :  Am.  Chem.  J.,  16,43. 

150  grams  (81  cc.)  concentrated  sulphuric  acid. 
300  cc.  water. 


182 


ORGANIC   CHEMISTRY. 


100  grams  sodium  pyrochromate. 

150  cc.  water. 

75  grams  (95  cc.)  alcohol. 

Put  in  a  one  liter  distilling  bulb  300  cc.  of  water,  and 
150  grams  (81  cc.)  of  concentrated  sulphuric  acid.  Dis- 
solve loo  grams  of  sodium  pyrochromate  in  150  cc.  of 
water,  and  add  75  cc.  of  alcohol.  Put  a  stopper 
bearing  a  separatory  funnel  in  the  mouth  of  the  distill- 


Fig.  22. 

ing  bulb,  and  connect  a  second  quarter  liter  distilling 
bulb  to  its  side  tube  with  a  rubber  stopper.  Connect 
the  side  tube  of  the  second  bulb  to  a  condenser  which  is 
directed  upward,  by  running  the  side  tube  into  a  piece 
of  rubber  tubing  drawn  over  the  lower  end  of  the  con- 
denser. Connect  the  upper  end  of  the  condenser  with 
two  Drechsel  wash-bottles,  each  containing  about  25  cc. 
of  dry  ether.  Surround  the  latter  with  a  freezing 
mixture.  Put  the  small  distilling  bulb  into  a  dish  con- 


ALDEHYDES,  KETONES,  AND  DERIVATIVES.     183 

taining  water  at  45°— 50°,  and  feed  the  condenser  with 
water  at  30°.  Heat  the  dilute  sulphuric  acid  nearly  to 
boiling,  remove  the  flame,  and  drop  in  the  pyrochromate 
mixture  slowly.  The  reaction  may  proceed  as  rapidly 
as  is  possible  without  escape  of  aldehyde  through  the 
ether.  Outside  heating  is  not  usually  necessary  after 
the  reaction  has  commenced. 

When  all  the  mixture  has  been  added  and  the  alde- 
hyde driven  over  by  heating  for  a  short  time,  disconnect 
the  wash  bottles,  transfer  the  ethereal  solution  to  a  flask, 
set  the  latter  in  a  freezing  mixture,  and  pass  in  ammonia 
gas,  generated  by  boiling  strong  aqua  ammonia  (0.90 
sp.  gr.) ,  and  dried  by  passing  it  over  quicklime,  or  soda- 
lime  in  a  drying  cylinder.  Use  a  wide  delivery  tube 
for  the  gas  to  prevent  its  being  stopped  by  the  alde- 

OTT 
hyde  ammonia,  CH8CH<,^Tj  ,  which  is  formed.     Pass 

the  gas  till  the  solution  smells  of  ammonia  strongly, 
and  allow  the  whole  to  stand  for  an  hour.  Filter  off  the 
crystals,  and  allow  them  to  stand  on  filter  paper  for  a 
short  time.  They  can  be  kept  for  some  time  in  tightly 
stoppered  tubes  or  bottles,  containing  ammonia  gas. 
Yield  about  15  grams. 

Aldehyde  may  be  prepared  from  them  by  dissolving 
them  in  their  own  weight  of  water,  and  dropping  the 
solution  into  4  parts  of  50  per  cent,  sulphuric  acid,  con- 
densing the  aldehyde  which  is  generated,  with  a  con- 
denser containing  ice-water,  and  collecting  in  a  flask 
surrounded  with  a  freezing  mixture. 

Aldehyde  boils  at  21°,   and  has  a  specific  gravity  of 


184  ORGANIC   CHEMISTRY. 

0.7951  at  10°.  When  warmed  with  caustic  potash  it  is 
converted  into  a  resin.  It  reduces  a  cold  ammoniacal 
solution  of  silver  nitrate  (3  grams  AgNO3, 33  cc.  NH4OH, 
sp.  gr.  0.90,  30  cc.  10  per  cent,  sodium  hydroxide),  a 
general  reaction  for  aldehydes.  A  drop  of  concentrated 
sulphuric  acid  converts  it  into  paraldehyde,  C6H12O8, 
which  melts  at  10.5°,  and  boils  at  124°.  Hydrochloric 
acid  gas  converts  it  into  a  mixture  of  metaldehyde, 
C6H12OS,  and  paraldehyde.  Metaldehyde  decomposes 
on  standing,  being  converted  partly  into  paraldehyde 
and  partly  in  tetraldehyde,  C8H16O4.  Paraldehyde  and 
metaldehyde  are  probably  stereomeric  compounds. 

71.  Preparation  of  a  Ketone  by  Condensation  of  an 
Acid  Chloride  with  Benzene  by  Means  of  Aluminium 

Chloride.  —  Benzophenone,  C6H6COC6HB.  (Diphenyl- 
methanone.) 

Literature. — Peligot :  Ann.  Chem.  (Liebig),  12,  41 ;  Chancel : 
Ibid,  72,  279;  Otto  :  Ber.  d.  chem.  Ges.,  3,  197  ;  Friedel,  Crafts  : 
Ann.  chim.  Phys.,  [6],  1,510,  518;  Zincke :  Ann.  Chem.  (Lie- 
big),  159,  377  ;  Friedel,  Crafts,  Ador  :  Ber.  d.  chem.  Ges.,  10, 
1854;  Stockhausen  and  Gattermann  :  Ber.  d.  chem.  Ges.,  25, 
3521;  Radziewanowski :  Ibid,  27,  3235;  28,  1135;  Crafts:  Am. 
Chem.  J.,  5,  324. 

20  grams  benzene. 

20  grams  benzoyl  chloride. 

100  grams  carbon  disulphide. 

20  grams  aluminium  chloride. 

Put  in  a  flask  20  grams  of  benzene,  20  grams  of  ben- 
zoyl chloride,  and  100  grams  of  carbon  disulphide.  Add 
in  small  portions,  during  about  ten  minutes,  20  grams 


ALDEHYDES,  KETONES,  AND  DERIVATIVES.     185 

of  finely  powdered  aluminium  chloride .  ( See  84,  p .  211.) 
The  chloride  should  be  exposed  to  the  air  as  little  as  pos- 
sible. Connect  with  a  reversed  condenser,  and  heat  on 
the  water-bath  for  two  to  three  hours,  or  till  the  evolution 
of  hydrochloric  acid  nearly  ceases.  Distil  off  the  carbon 
disulphide,  and  pour  the  residue  into  300  cc.  of  water  in 
a  flask,  cooling,  if  necessary.  Add  TOCC.  of  concentrated 
hydrochloric  acid,  and  pass  a  rapid  current  of  steam 
through  the  liquid  for  a  short  time  to  expel  the  rest  of 
the  benzene  and  carbon  disulphide.  Collect  the  benzo- 
phenone  with  some  ether,  separate,  wash  the  ethereal 
solution  by  shaking  it  several  times  with  water,  and  with 
a  solution  of  sodium  hydroxide,  dry  it  with  calcium 
chloride,  and  fraction  the  residue,  after  distilling  off  the 
ether,  using  a  small  distilling  bulb,  and  collecting  the 
distillate  directly  in  a  test-tube,  or  preparation  tube, 
without  using  a  condenser.  Yield  20  to  21  grams. 
Benzophenone  melts  at  48.5°,  and  boils  at 

303.7°  under  723.05  mm. 
304-5°  735-45 

305-5°  750.91 

306.1°      "       760.32     " 
306.4°      "       765.06     " 

This  table  is  of  especial  value  for  testing  thermome- 
ters. (See  p.  16.) 

When  benzophenone  is  warmed  with  hydroxylamine 
hydrochloride,  caustic  soda  in  excess,  and  alcohol,  for  two 
hours,  an  oxime  melting  at  140°  is  formed.  If  this  oxirne, 
dissolved  in  dry  ether,  is  treated  successively  with  one 
and  a  half  times  its  weight  of  phosphorus  pentachloride, 


1 86  ORGANIC   CHEMISTRY. 

and  with  water,  it  is  converted  into  benzanilide  (Beck- 
mann's  rearrangement). 

CeH6— C— C6H6+PC16  =  C6H6— C— C6H5+POC13+HC1 

II  II 

NOH  N— Cl 

C6HB— C— CeH6  =  CPH6— C— Cl 

II  II 

N— Cl  N— C5H 

C6HB— C— Cl     +  H2O  =  CBHB— C=O 

II  I  +HC1. 

N— C6H6  HN— C6H5 

The  study  of  this  reaction  has  been  of  great  value  in 

the  development  of  theories  about  the  stereochemistry 

of  nitrogen.     Unsymmetrical  oximes  which  occur  in  two 

forms,  as,  for  instance,  monobrombenzophenone  oxime, 

'  C6H4BrCC6H6,  may  be  rearranged  in  this  manner,  and 

II 
NOH 

each  form  gives  a  different  product ;  viz. ,  brombenzoyl- 
anilide  and  benzoylbromanilide. 

C6H4Br— C— C6HB     —     C6H4BrCONHC6HB. 

II 
NCI 

C6H4Br— C— C6HB     — *     CflH5CONHC6H4Br. 

II 
Cl— N 

The  two  compounds  can  be  distinguished  by  their 
saponification  products. 


ALDEHYDES,    KETONES,    AND   DERIVATIVES.        187 

72.  Preparation  of  an  Aldehyde  by  Treatment  of  a 
Monochlor  Derivative  of  an  Aromatic  Hydrocarbon 

with  a  Nitrate.— Benzaldehyde,  C6H6C^Q.      (Oil    of 

bitter  almonds.) 

Literature.— Liebig,  Wohler  :  Ann.  Chem.  (Liebig),  22,  i; 
Cannizzaro  :  Ibid,  88, 180  ;  Dumas,  Peligot :  Ibid,  14,  40  ;  Guck- 
elberger :  Ibid,  64,  60,  72,  86 ;  L,auth,  Grimaux :  Bull.  Soc. 
Chim.,  7,  106  ;  Baeyer :  Ann.  Chem.  (Liebig),  140,  296  ;  Piria  : 
Ibid,  100,  105;  Ivitnpricht:  Ibid,  139,  319;  Anschiitz ;  Ibid,  226, 
18. 

40  grams  benzyl  chloride. 

40  grams  barium  nitrate. 

300  cc.  water. 

Put  in  a  500  cc.  round-bottomed  flask  40  grams  of 
benzyl  chloride,  40  grams  of  barium  nitrate  (or  30  grams 
calcium  nitrate,  prepared  by  treating  an  excess  of  cal- 
cium carbonate  with  the  theoretical  amount  of  nitric 
acid,  and  filtering),  and  300  cc.  of  water.  Connect  with 
an  upright  condenser,  best  with  a  rubber  tube  slipped 
over  the  neck  of  the  flask,  the  condenser  reaching  well 
down  into  the  neck  of  the  latter,  so  that  the  nitrous 
fumes  evolved  will  come  but  little  in  contact  with  the 
rubber.  The  connection  must  be  tight.  Put  in  the 
top  of  the  condenser  a  rubber  stopper  bearing  a  tube, 
which  reaches  down  into  the  liquid,  and  also  a  tube 
which  will  convey  the  gases  coming  from  the  condenser 
to  the  bottom  of  a  150  cc.  bottle,  or,  better,  of  a  large 
tube,  closed  below.  Pass  through  the  first  tube  a  slow 
current  of  carbon  dioxide,  and  boil  the  contents  of  the 
flask  gently  on  a  wire  gauze  for  six  to  eight  hours,  or 


1 88  ORGANIC   CHEMISTRY. 

till  the  odor  of  the  benzyl  chloride  nearly,  or  quite  dis- 
appears. Some  such  means  as  that  described  for  the 
exclusion  of  the  air  is  essential  to  prevent  the  oxidation 
of  the  aldehyde  to  benzoic  acid. 

Extract  the  benzaldehyde  with  ether,  distil  off  the 
latter,  and  shake  the  residue  with  three  or  four  times  its 
volume  of  a  strong  solution  of  acid  sodium  sulphite,1  in 
a  stoppered  bottle.  After  some  time,  filter  off  the  bi- 
sulphite compound,  and  wash  successively  with  a  very 
little  water,  alcohol,  and  ether.  Put  the  compound  in  a 
distilling  bulb  with  an  excess  of  a  strong  solution  of 
sodium  carbonate,  and  distil  with  steam.  Extract  the 
benzaldehyde  from  the  distillate  with  ether,  dry  with 
calcium  chloride,  and  distil.  Yield  10  to  15  grams. 

Benzaldehyde  melts  at  — 13°. 5,  and  boils  at  179°.  It 
has  a  specific  gravity  of  1.0504  at  15°.  It  oxidizes 
slowly  on  standing  in  the  air,  when  pure.  It  is  more  sta- 
ble when  it  contains  hydrocyanic  acid,  which  is  usually 
added  to  the  commercial  article  for  this  reason.  It  dis- 
solves in  300  parts  of  water,  but  is  easily  soluble  in  alco- 
hol, and  ether. 

73.  Condensation   of  an   Aldehyde   with    Itself    by 
Means  of  Potassium  Cyanide. — Benzoin, 
C6HBCHOHCOC6H5. 

Literature. — Liebig  and  Wohler  :  Ann.  Chem.  (Laebig),  3, 
276;  Zincke:  Ibid,  198,  151;  Papcke  :  Ber.  d.  chem.  Ges.,  21, 
1335  ;  A.  Smith  and  Ransom  :  Am.  Chem.  J.,  16,  108. 

1  This  must  be  freshly  prepared  by  passing  sulphur  dioxide  into  a  mix- 
ture of  acid  sodium  carbonate  with  three  parts  of  water,  till  the  solution 
smells  strongly  of  the  gas.  For  sulphur  dioxide,  see  p.  172. 


ALDEHYDES,    KETONES,    AND    DERIVATIVES.       189 

20  grams  benzaldehyde. 

2  grams  potassium  cyanide. 

50  cc.  alcohol. 

40  cc.  water. 

Boil  the  mixture  given  above  with  an  upright  con- 
denser for  half  an  hour.  Cool,  filter,  wash  with  dilute 
alcohol,  and  crystallize  from  a  little  hot  alcohol.  A  lit- 
tle more  benzoin  may  be  obtained  by  adding  a  little 
more  potassium  cyanide  to  the  filtrate,  and  boiling  again 
for  a  quarter  of  an  hour.  Yield  15  to  18  grams. 

Benzoin  melts  at  134°,  and  boils  with  some  decomposi- 
tion at  320°.  By  warming  on  the  water-bath  for  two 
hours  with  two  and  one- half  times  its  weight  of  nitric 
acid  (sp.  gr.  1.33),  with  frequent  shaking,  it  is  oxidized 
to  benzil,  C6HBCOCOC6H6.  This  body  has  been  of  un- 
usual interest,  because  of  the  part  which  its  compounds 
have  played  in  the  development  of  the  theories  of  stereo- 
chemistry. It  forms  two  monoximes  and  three  dioximes, 
to  which  the  following  stereometric  formulae  have  been 
given  : 

C.H.— C— CO— C.H.,  C6H6— C— CO— C6HB, 

I!  II 

HO— N                                                  N— OH 
C6H6— C— C— CeH5,         C8H6— C C— C6H6, 

II     II  II  II 

HO— N    N— OH  N— OH   HO— N 

C.H.-C C-C6HB. 

II  II 

HO— N  HO— N 

Some  suppose  that  the  differences  are  due  to  struc- 


1  90  ORGANIC   CHEMISTRY. 

tural  isomerism  and  not  to  stereoisomerism.  See  Wit- 
tenberg and  V.  Meyer:  Ber.  d.  chem.  Ges.,  16,  503; 
Auwers  and  V.  Meyer:  Ibid,  21,  784,  3510  ;  22,  537,  564, 
1985,  1996;  Hantsch  and  Werner:  Ibid,  23,  n,  1243. 

By  means  of  fuming  hydriodic  acid  benzoin  may  be 
reduced  to  dibenzyl,  C6HBCH3CHaC6H6. 

74.  Oxidation  a  of  Hydrocarbon  to  a  Quinone.  —  An- 

CO 

thraquinone,  C6H4(         )C6H4. 


Literature.—  Laurent,  Berzelius  :  Jsb.  d.  chem.,  16,  366;  An- 
derson: Ann.  Chem.  (Liebig),  122,  301  ;  Kekule",  Franchimont  : 
Ber.  d.  chem.  Ges.,  5,  908;  Ullmann  :  Ann.  Chem.  (Liebig), 
291,  24;  W.  H.  Perkin,  Jr.;  J.  Chem.  Soc.,  59,  1012;  Graebe, 
Liebermann  :  Ann.  Chem.  (Liebig),  Supl.,  7,  285. 

10  grams  anthracene. 

17  grams  chromic  anhydride. 

100  cc.  glacial  acetic  acid. 

Put  10  grams  of  anthracene,  and  75  cc.  glacial  acetic 
acid  in  a  flask  connected  with  an  upright  condenser, 
heat  to  boiling,  and  add,  slowly,  17  grams  of  chromic 
anhydride,  dissolved  in  the  smallest  possible  amount  of 
water,  and  the  solution  diluted  with  25  cc.  glacial  acetic 
acid.  Boil  for  five  to  ten  minutes,  pour  the  solution 
into  water,  filter,  and  wash.  Dry  the  residue,  and  crys- 
tallize it  from  glacial  acetic  acid,  or  from  toluene.  It 
may  also  be  purified  by  sublimation  (see  p.  174).  Yield 
almost  quantitative,  if  the  anthracene  is  pure. 

Anthraquinone  sublimes  in  yellow  needles,  which 
melt  at  273°,  and  boil  at  379°-38i°.  100  parts  of  toluene 


ALDEHYDES,    KETONES,    AND    DERIVATIVES.        IQI 

dissolve  0.19  parts  at  15°,  and  2.56  parts  at  100°.     By 
distilling  with  zinc  dust  anthracene  is  regenerated. 

75.  Preparation  of  Phenyl  Hydrazone. — Phenyl  hy- 

r\  TT 

drazone  of  acetophenone,   CH>C  =  N— NHC6H6. 

Literature. — B.  Fischer  :  Ber.  d.  chem.  Ges.,  17,  573  ;  22,  90  ; 
16,  2241  ;  Overton:  Ibid,  26,  20;  Reisenegger,  Ibid,  16,  661. 

5  cc.  acetic  acid  (30  per  cent.). 

1.5  cc.  phenyl  hydrazine. 

i  cc.  acetophenon. 

Dissolve  1.5  cc.  of  phenyl  hydrazine  in  5  cc.  of  acetic 
acid  (30  per  cent.)  in  a  test-tube,  add  i  cc.  of  acetophe- 
none, and  shake  vigorously  till  the  hy drazone  separates 
in  crystalline  form.  Filter,  wash  with  water,  dissolve 
in  a  very  small  beaker,  in  a  little  hot  alcohol,  add  water 
till  the  hot  solution  begins  to  grow  turbid,  and  allow  to 
crystallize. 

The  hydrazone  of  acetophenone  is  very  easily  ob- 
tained and  purified.  In  some  cases,  where  there  is  dif- 
ficulty in  obtaining  a  crystalline  product,  Overton  (loc. 
tit. )  recommends  to  dissolve  the  ketone  in  a  little  glacial 
acetic  acid,  add  a  slight  excess  of  phenyl  hydrazine,  and 
allow  the  mixture  to  stand  in  the  cold  till  the  hydrazone 
separates. 

Acetophenone  phenyl  hydrazone  crystallizes  from  dilute 
alcohol  in  leaflets,  which  melt  at  105°.  It  is  decomposed 
by  concentrated  hydrochloric  acid  into  phenyl  hydrazine 
hydrochloride,  and  acetophenone.  By  sodium  amalgam, 
in  alcoholic  solution,  it  is  reduced  to  a  mixture  of  aniline 
and  phenyl  methyl  carbinamine,  C6H6CHNH2CH8 
( i '  -aminoethy  Iphen ) . 


IQ2  ORGANIC   CHEMISTRY. 

76.  Preparation  of  an  Oxime.  —  A  cetoxime, 
OTT 


(Isonitroso   acetone    or   propanone 
oxime)  . 

Literature.—  V.  Meyer  and  Janny  :  Ber.  d.  chem.  Ges.,  15,  1324, 
1529  ;  Janny  :  Ibid,  16,  170  ;  V.  Meyer  and  Wege  :  Ann.  Chem. 
(Liebig),  264,  121;  Dodge:  Ibid,  264,  185;  Beckmann  :  Ber  d. 
chem.  Ges.,  ai,  767  ;  Auwers  :  Ibid,  22,  604. 

15  grams  hydroxylamine  hydrochloride. 

14  grams  (17  cc.)  acetone. 

8  grams  sodium  hydroxide. 

50  cc.  water. 

Put  in  a  loocc.  glass-stoppered  bottle,  15  grams  of  hy- 
droxylamine hydrochloride,  and  17  cc.  of  acetone,  and 
add  a  solution  of  8  grams  of  sodium  hydroxide  in  50  cc.  of 
water.  Shake  and  cool  somewhat,  stopper  tightly,  and 
allow  to  stand  for  twenty-  four  hours.  Extract  the  solu- 
tion three  times  with  about  20  cc.  of  ether,  the  ether  be- 
ing distilled  off  and  used  again  each  time,  because  of  the 
volatility  of  the  acetoxime.  The  last  time  distil  only 
about  one-half  of  the  ether,  transfer  the  remainder  of 
the  ethereal  solution  to  a  crystallizing  dish,  and  allow 
the  ether  to  evaporate  spontaneously,  or  better  in  vacua 
over  sulphuric  acid.  As  soon  as  the  crystals  are  dry, 
transfer  to  a  well  stoppered  bottle,  as  the  substance  is 
quite  volatile.  Yield  14  to  15  grams. 

In  the  preparation  of  acetoxime,  it  is  necessary  to 
use  the  sodium  hydroxide  and  hydroxylamine  in  equiv- 
alent amounts,  as  the  acetoxime  cannot  be  extracted 
from  an  acid  or  an  alkaline  solution.  Auwers  has 


ALDEHYDES,    KETONES,    AND    DERIVATIVES.        1  93 

shown,  however,  that  in  some  cases  the  formation  of  an 
oxime  is  facilitated  by  using  about  three  times  the  theo- 
retical amount  of  sodium  hydroxide. 

Acetoxime  crystallizes  in  prisms,  which  melt  at  59°- 
60°.  It  boils  at  134.8°  under  728  mm.  pressure.  It  is 
very  easily  soluble  in  water,  alcohol,  ether,  and  ligroin. 
It  can  be  extracted  with  ether  only  from  neutral,  not 
from  acid,  or  alkaline  solutions.  It  is  decomposed  by 
boiling  with  hydrochloric  acid  into  acetone  and  hydrox- 
ylamine  hydrochloride. 

77.  Preparation  of  a  Semicarbazone  Compound.— 

OTT 
Semicarbazone  of  acetone,        s>C=N—  NH—  CONHa. 


Literature.  —  Thiele  and  Stange  :  Ann.  Chem.  (Liebig),  283, 
19  ;  Thiele  and  Henser  :  Ibid,  288,  281,  311  ;  Baeyer  :  Ber.  d. 
chem.  Ges.,  27,  1918. 

70  cc.  concentrated  sulphuric  acid. 

20  grams  nitrate  of  urea. 

Ice. 

20  grams  nitrourea. 

150  cc.  concentrated  hydrochloric  acid. 

70  grams  zinc  dust. 

Ice. 

Salt. 

20  grams  sodium  acetate. 

12  grams  acetone. 

Put  70  cc.  of  concentrated  sulphuric  acid  in  a  beaker 
and  cool  it  below  o°  with  a  freezing  mixture.      Add  20 


194  ORGANIC   CHEMISTRY. 

grams  of  dry  urea  nitrate,1  in  small  portions,  stirring, 
and  taking  care  that  the  mixture  does  not  rise  above 
2°-3°.  Allow  to  stand  for  half  an  hour,  but  not  after 
there  is  much  evolution  of  gas.  Pour  on  such  a  quan- 
tity of  ice  that  the  temperature  of  the  mixture  is  about 
30°.  Cool,  filter,  wash  slightly,  and  suck  as  dry  as  pos- 
sible. Stir  it  with  150  cc.  of  concentrated  hydrochloric 
acid,  previously  cooled  to  o°,  and  containing  some  pieces 
of  ice.  Pour  in  small  portions,  into  a  mixture  of  70 
grams  of  zinc  dust,  with  powdered  ice,  keeping  the  whole 
in  a  beaker,  or,  especially  in  working  with  larger  quan- 
tities in  a  granite  iron  dish,  placed  in  a  freezing  mix- 
ture. The  temperature  should  be  kept  at  about  o°,  but 
the  use  of  much  ice  in  the  solution  should  be  avoided, 
because  of  the  resulting  dilution.  After  all  has  been 
added,  allow  to  stand  for  a  short  time,  filter,  add  salt  to 
saturation,  and  20  grams  of  sodium  acetate,  and  filter 
again,  if  necessary.  These  operations  should  be  carried 
through  rapidly,  and  the  solution  not  allowed  to  become 
warm.  Add  12  grams  (15  cc.)  of  acetone,  stir  thor- 
oughly, and  allow  to  stand  for  some  hours,  if  necessary 
over  night,  in  a  freezing  mixture,  or  till  the  double 
compound  of  zinc  with  the  acetone  semicarbazone, 

=N~  NH~  C0~  NH"      ZnC1" 


has   separated  as   completely   as   possible.     Filter    off, 
wash    with    a    little    salt    solution,    and    a    little  ice- 

i  This  may  be  prepared  as  follows  :  Dissolve  12  grams  of  urea  in  12  cc. 
of  water,  and  pour  the  solution  into  20  cc.  of  concentrated  nitric  acid,  diluted 
with  20  cc.  of  water.  Cool  thoroughly,  filter  on  a  plate,  and  dry  on  filter- 
paper,  or  porcelain.  20  to  22  grams  should  be  obtained. 


ALDEHYDES,  KETONES,  AND  DERIVATIVES.     195 

water.  16  to  18  grams  of  the  compound  should  be  ob- 
tained. 

By  adding  some  benzaldehyde  to  the  filtrate,  stirring 
thoroughly,  and  allowing  to  stand,  a  small  quantity  of 
the  semicarbazone  of  benzaldehyde  can  be  obtained. 

To  obtain  the  acetone  semicarbazone,  digest  15  grams 
of  the  salt  with  30  cc.  of  concentrated  ammonia  for  some 
time,  and  filter. 

To  prepare  the  hydrochloride  of  semicarbazide,  add  to 
the  acetone  compound  twice  its  weight  of  concentrated 
hydrochloric  acid,  and  filter  through  a  funnel  loosely 
plugged  with  asbestos.  Allow  the  solution  to  stand  in 
a  vacuum  desiccator  containing  soda-lime  and  concen- 
trated sulphuric  acid,  till  it  evaporates  nearly  to  dry- 
ness.  Dry  the  crystals  of  the  chloride  on  porous  porce- 
lain. 

Acetone  semicarbazone  crystallizes  in  needles,  which 
melt  with  decomposition  at  187°.  It  is  moderately  solu- 
ble in  cold  water,  less  soluble  in  alcohol,  insoluble  in 
ether.  It  reduces  an  ammoniacal  alkaline  silver  solu- 
tion immediately.  It  is  easily  decomposed  by  mineral 
acids,  even  in  the  cold. 

The  hydrochloride  of  semicarbazide,  NH2CO — NH — 
NH2 — HC1,  crystallizes  in  prisms,  which  melt  at  173°  with 
decomposition.  It  dissolves  very  easily  in  water,  less 
easily  in  hydrochloric  acid,  and  is  almost  insoluble  in 
alcohol,  and  ether.  It  is  decomposed  by  heating  with 
acids  and  alkalies.  It  condenses  readily  with  most 
ketones  and  aldehydes,  forming  usually  well  crystal- 
lized compounds. 


196  ORGANIC   CHEMISTRY. 

For  the  preparation  of  semicarbazones,  Baeyer  and 
Thiele  recommend  to  dissolve  the  hydrochloride  of  semi- 
carbazide  in  a  little  water,  add  the  calculated  amount  of 
an  alcoholic  solution  of  potassium  acetate  and  the  ketone, 
and  then  alcohol  and  water  to  complete  solution.  The 
reaction  is  complete  in  a  few  minutes  in  some  cases,  in 
others  it  requires  4  to  5  days.  When  complete,  the  ad- 
dition of  water  will  usually  cause  the  separation  of  a 
substance  which  is  entirely  crystalline. 

78.    Preparation    of    Furfural    from    a    Pentose. — 

CH— CH 

II         II 

CH     C— CHO. 
\X 
O 

Literature. — Hill:  Am.  Chem.  J.,  3,  33  ;  Stone:  Ber.  d.  chem. 
Ges.,  24,  3019;  Am,  Chem.J.,  13,  73,  348;  Giinther,  de  Chalmot 
and  Tollens  :  Ber.  d.  chem.  Ges.,  23,  3575 ;  Stone  and  Tollens : 
Ann.  Chem.  (lyiebig),  249,  227;  Allen  and  Tollens  :  Ibid,  260, 
291  ;  Stone  :  J.  Anal.  Appl.  Chem.,  5,  421. 

ioo  grams  cobs  of  Indian  corn. 

500  cc.  hydrochloric  acid  (sp.  gr.   1.06). 

Put  in  a  liter  distilling  bulb  ioo  grams  of  coarsely 
powdered  corn  cobs  (or  wheat  straw,  or  wheat  bran, 
but  the  yield  will  be  smaller),  and  500  cc.  of  hydro- 
chloric acid,  of  specific  gravity  1.06  (140  cc.  acid  of  sp. 
gr.  i.i i,  and  360  cc.  of  water).  Fit  in  the  mouth  of 
the  bulb  a  cork  bearing  a  separatory  funnel,  and  con- 
nect with  a  condenser.  Heat  to  boiling,  and  distil 
slowly,  at  the  rate  of  about  200  cc.  in  an  hour,  dropping 
in  dilute  hydrochloric  acid  (75  cc.  acid  sp.  gr.  i.n,  to 


ALDEHYDES,    KETONES,    AND   DERIVATIVES.        197 

500  cc.  of  water),  at  such  a  rate  as  to  keep  the  contents 
of  the  bulb  constant  in  volume.  Continue  the  distilla- 
tion for  three  hours,  or  till  600-700  cc.  have  distilled. 
Add  a  drop  of  methyl  orange,  and  nearly  neutralize  the 
distillate  with  a  strong  solution  of  caustic  soda;  add  150 
grams  of  salt,  and  distil  off  about  200  cc.  Add  60 
grams  of  salt  to  the  distillate,  and  extract  with  ether. 
Dry  the  solution  with  calcium  chloride,  distil  off  the 
ether,  and  distil  the  furfural  which  remains.  Yield  1 1 
to  12  grams. 

Certain  gums  contained  in  the  materials  used  are  hy- 
drolyzed  by  the  dilute  acid,  with  the  formation  of  a  pen- 

CHaOH 

CHOH 
tose,  CHOH.      The  pentose  then  condenses  to  furfural. 

CHOH 

CHO 

Furfural  is  a  colorless  oil,  which  boils  at  161°,  and 
has  a  specific  gravity  of  1.1636  at  13.5°.  Its  odor  re- 
sembles that  of  benzaldehyde.  By  boiling  with  potas- 
sium cyanide,  in  dilute  alcoholic  solution,  it  is  con- 

C4H3O— CHOH 
verted  into  furom,  ,  in  the  same  manner 

C4H3O— CO 

in  which  benzaldehyde  is  converted  into  benzoin  (see 
73,  p.  1 88) .  It  condenses  easily  with  ammonia  in  aqueous 
solution  to  furfuramide,  (C5H4O)3N2,  which  is  difficultly 
soluble.  It  gives  a  hydrazone  with  phenyl  hydrazine, 
and  gives  a  red  compound  with  aniline  acetate.  Filter 
paper  moistened  with  aniline  acetate,  furnishes  a  very 
sensitive  qualitative  test  for  furfural. 


IX. 


Sulphonic  Acids  and  Sulphine  Compounds* 

In  the  aliphatic  series  sulphonic  acids  are  obtained  by 
the  oxidation  of  mercaptans  (sulphur  alcohols),  with 
nitric  acid,  or  with  potassium  permanganate. 

RSH  +  3O  =  R—  S02.OH. 

They  are  also  formed  by  heating  the  sodium  salt  of 
an  acid  ester  of  sulphuric  acid  with  sodium  sulphite  in 
concentrated  solution  at  a  temperature  of  iio°-i2O°. 
(Mayer  :  Ber.  d.  chem  Ges.,  23,  909). 

R—  O—  SO2—  O—  lSTa+NaaSO8  =  R—  SO2ONa+Na.SO4. 

Fatty  acids  react  with  sulphur  trioxide,  and  their  an- 
hydrides with  sulphuric  acid,  or  with  the  chloride  of 

Cl 
sulphuric  acid   SOa^'  to  form  sulphonic  acids,  which 


contain  both  sulphonic  and  carboxyl  groups,  and  are 
bibasic.  The  sulphonic  group  usually  combines  with 
the  <*-carbon  atom. 

In  the  aromatic  series  sulphonic  acids  are  almost  ex- 
clusively prepared  by  the  action  of  sulphuric  acid,  sul- 
phur trioxide,  the  fuming  acid,  the  chloride  of  the 
acid  on  hydrocarbons  and  their  derivatives.  The  sul- 
phonic group  usually  enters  into  the  para  or  ortho  posi- 
tion with  regard  to  NH4,  OH,  CH3,  OR,  Cl,  Br,  I,  but 
in  the  meta  position  with  regard  to  CO2H,  SO3H,  COH, 
COCH3,  CN,  CC13,  or  NO2.  As  with  nitration,  homo- 


SUI<PHONIC  ACIDS  AND  SUIyPHINK  COMPOUNDS.     1  99 

logues  of  benzene  are  more  easily  sulphonated  than  ben- 
zene itself.  The  strength  of  the  acid  to  be  used,  and  the 
temperature,  vary  with  different  cases,  and  must  be  es- 
tablished by  trial  with  small  amounts,  or  by  a  consider- 
ation of  the  conduct  of  analogous  bodies. 

RH  +  H2SO4  =  R—  S02OH  +  H2O. 
RH  +  S03HC1  =  RS02C1  +  H2O. 
The  sulphonic  acids  are,  in  most  cases,  easily  soluble 
in  water,  and  as  a  large  excess  of  sulphuric  acid  must  be 
used  for  their  preparation,  it  is  usually  necessary  to 
separate  the  acids  after  dilution  with  water.  Two 
methods  are  commonly  used.  The  older  method  and 
the  one  almost  universally  applicable,  consists  in  neu- 
tralizing the  diluted  solution  with  calcium  carbonate,  or 
barium  carbonate,  and  filtering  from  the  insoluble  sul- 
phates, the  calcium  and  barium  salts  of  the  sulphonic 
acids  being  usually  soluble  in  water.  From  these  salts 
the  sodium  or  potassium  salts  can  then  be  prepared,  by  use 
of  sodium  or  potassium  carbonate.  The  second  method 
consists  in  saturating  the  diluted  solution  with  salt, 
which  will,  in  many  cases,  cause  the  precipitation  of  the 
sodium  salt,  even  in  cases  where  the  latter  is  compara- 
tively easily  soluble  in  pure  water  (see  25,  p.  84  and  67, 

P-  173). 

Sulphine  compounds  are  prepared  by   treating  alkyl 
sulphides  with  alkyl  iodides,  or  by  treating  metallic  sul- 
phides with  an  excess  of  an  alkyl  iodide. 
R2S  +  RI  =  R3SI. 

R\ 

Na2S  +  3RI  =  R—  SI  +  2NaI. 
R/ 


200  ORGANIC   CHEMISTRY. 

The  sulphine  hydroxide  can  be  prepared  from  the 
iodides,  or  other  halogen  salts,  by  treatment  with  silver 
oxide  and  water.  The  sulphine  hydroxides  are  strong 
bases,  resembling  the  quaternary  ammonium  hydroxides, 
and  the  iodoso  compounds. 

79.  Preparation  of  a  Sulphonic  Acid  of  an  Amine.  — 
Sulphanilic  acid,  0^4<  (Paraamino- 


sulphobenzene.) 

Literature.  —  Gerhardt:  Ann.  Chem.  (Ljebig),  60,310;  Buck- 
ton,  Hofmann  :  Ibid,  100,  163  ;  Limpricht,  Ibid,  177,  80  ;  Laar  ; 
Ber.  d.  chem.  Ges.,  14,  1933  ;  Schmitt  ;  Ann.  Chem.  (Liebig), 
120,  132  ;  Winther  :  Ber.  d.  chem.  Ges.,  13,  1941. 

30  grams  aniline. 

90  grams  (50  cc.)  concentrated  sulphuric  acid. 

Put  90  grams  of  concentrated  sulphuric  acid  in  a  small 
flask,  add  in  small  portions,  with  shaking,  30  grams  (30 
cc.)  of  aniline,  and  heat  in  an  oil-bath  at  i8o°-i9O°  for 
four  to  five  hours,  or  until  a  drop  of  the  solution,  after 
diluting,  and  adding  caustic  soda,  shows  no  separation 
of  aniline.  Allow  to  cool,  pour  into  250  cc.  of  cold 
water,  cool,  filter,  and  wash.  Recrystallize  from  hot 
water,  adding  a  little  bone-black.  Yield  30-35  grams. 

Sulphanilic  acid  crystallizes  with  two  molecules  of 
water,  in  rhombic  plates  which  effloresce  readily.  It 
dissolves  in  166  parts  of  water  at  10°.  It  carbonizes  on 
heating  to  28o°-3OO°.  It  forms  no  salts  with  acids. 

The  sodium  salt,   C6H4<^JNa   +    2HaO,    and    the 

barium  salt,    (CeH4<^J  )  Ba   +  3iH3O,    crystallize 
well. 


SUIyPHONIC  ACIDS  AND  SUI^PHINK  COMPOUNDS.     2OI 

Sulphanilic  acid  is  used  in  water  analysis  for  the  esti- 
mation of  nitrites  (see  59,  p.  158)  .  The  sulphonic  deriva- 
tives of  amines  are  of  great  technical  importance,  since 
the  sulphonic  group  furnishes  the  "  auxochrome"  group 
necessary  for  dyestuffs  (seep.  150).  Sulphanilic  acid, 

metanilic  acid,  C6H4<gO  J^   >*(,  and  the  sulphonic  acids 

of  a-  and  /?-naphthylamine  are  especially  used  in  the 
preparation  of  azo  dyes. 

So.  Preparation  of  Sulphochlorides  and  Sulphon- 
amides  by  the  use  of  the  Chloride  of  Sulphuric  Acid.  — 

OTT 

o-  and  /-toluene  sulphonamides,   C6H4<CoQ  jq-jj 

Literature.  —  Remsen  and  Fahlberg:  Am.  Chem.  J.,  I,  427; 
Claesson  and  Wallin  :  Ber.  d.  chem.  Ges.,  12,  1848:  Noyes  :  Am. 
Chem.  J.,  8,  176;  Fahlberg,  Patents:  Ber.  d.  chem.  Ges.,  19,  R. 
374,  471  ;  Miiller:  Ibid,  12,  1348;  Terry:  Ann.  Chem.  (Liebig), 
169,  27. 

loo  grams  sulphuric  acid  monochloride. 

40  grams  toluene. 

Put  in  a  flask  100  grams  of  the  chloride  of  sulphuric 

Cl   l 
acid,     SO2<TT  place  it  in  cold  water,  and  drop  in  very 


slowly,    with  thorough   cooling,  40  grams  of  toluene. 
When  all  has  been  added,  pour  the  solution  carefully 

1  The  chloride  of  sulphuric  acid  can  be  prepared  by  putting  strongly 
fuming  or  crystallized  pyrosulphuric  acid  in  a  distilling  bulb,  fitting  a  tube 
passing  into  the  acid  to  the  neck  of  the  bulb  with  a  stopper,  made  by  wrap- 
ping it  with  thick,  soft  asbestos  paper,  and  passing  in  dry  hydrochloric  acid 
gas  while  the  contents  of  the  bulb  is  warmed.  The  chloride  will  distil  over. 
The  arrangement  of  condenser  and  receiver  should  be  similar  to  that  for 
acetyl  chloride  (see  20,  p.  77). 


202  ORGANIC    CHEMISTRY. 

into  cold  water.  The  mixed  sulphonchlorides  will 
mostly  solidify  after  a  short  time.  Filter  on  a  plate 
with  the  pump,  and  by  the  continuous  action  of  the 
pump,  and  the  repeated  addition  of  small  amounts  of 
water,  suck  through  so  much  as  possible  of  the  liquid 
chloride.  The  solid  chloride  remaining  is  nearly  pure 
paratoluenesulphonchloride,  and  after  thorough  drying 
on  porous  porcelain  it  may  be  kept  in  tightly-stoppered 
bottles,  or  it  may  be  converted  into  the  amide  by  treat- 
ment with  strong  aqua  ammonia. 

Separate  the  liquid  chloride  from  the  solution,  put  it 
in  a  test-tube  or  small  flask,  and  cool  it  to  — 20°  for  two 
hours,  with  a  freezing  mixture.  Filter  with  the  aid  of 
the  pump,  and  as  quickly  as  possible,  the  liquid  chlo- 
ride from  the  solid  which  separates.  Treat  the  liquid 
chloride  obtained  in  this  way  with  a  slight  excess  of 
strong  aqua  ammonia,  filter,  and  crystallize  the  amides 
formed  from  hot  water.  In  crystallizing,  treat  the 
amides  with  enough  water,  added  in  small  portions  to 
avoid  an  excess,  so  that  they  barely  dissolve  on  boiling; 
then  cool  to  about  70°,  and  keep  at  that  temperature  for 
some  time.  Most  of  the  orthoamide  will  separate,  and 
on  filtering  it  off,  and  recrystallizing  once,  it  will  be  pure. 
The  amides  which  separate  on  cooling  the  filtrate  can- 
not usually  be  separated  further  by  crystallization,  but 
by  boiling,  for  a  half  hour,  with  potassium  pyrochro- 
mate  (3  parts),  sulphuric  acid  (4%  parts),  and  water  (8 
parts) ,  the  parasulphonamide  may  be  oxidized  to  para- 
sulphaminebenzoic  acid,  while  the  orthoamide  is  partly 
destroyed,  and  partly  remains  unchanged.  By  cooling, 


SUIvPHONIC  ACIDS  AND  SULPHINE  COMPOUNDS.     203 

filtering,  washing,  and  boiling  the  residue  with  barium 
carbonate  and  water,  the  acid  is  converted  into  a  salt, 
and  on  filtering  hot,  and  cooling,  the  orthoatnide  will 
separate.  Yield  of  orthoamide  about  6  grams. 

Toluene  orthosulphochloride  is  an  oil,  the  parachlo- 
ride  melts  at  89°,  and  boils  at  i45°-i46°,  under  a  pres- 
sure of  15  mm.  Tolueneorthosulphonamide  crystallizes 
in  octahedral  crystals,  which  melt  at  155°,  and  dissolve 
in  958  parts  of  water  at  9°.  Tolueneparasulphonamide 
crystallizes  in  leaflets,  which  melt  at  137°,  and  dissolve 
in  515  parts  of  water  at  9°. 

The  orthoamide  is  oxidized  by  potassium  permanga- 
nate, in  faintly  alkaline  solution,  tobenzoic  sulphinide, 


C.H  '        /NH,    (''saccharine")  which  is  200  times 


as  sweet  as  cane  sugar.  In  strongly  alkaline  solutions 
it  is  oxidized  by  potassium  permanganate,  or  potassium 
ferricyanide,  to  orthosulphaminebenzoic  acid, 

CO.H 
C6H4( 

XSO3NH2 

81.  Preparation  of  a  Sulphine  Compound.  —  Trimeth- 

CH3\ 

ylsulphine    iodide,    CH3—  SI. 
CH8/ 

Literature.  —  Oefele  :  Ann.  Chem.  (Liebig),  132,  82;  Cahours  : 
Ibid,  135,355;  Klinger:  Ber.  d.  chem.  Ges.,  10,  1880;  15,881; 
Masson  and  Kirkland  :  J.  Chem.  Soc.,  1889,  135  ;  Dehn  :  Ann. 
Chem.  (Liebig),  Supl.,  4,  106;  Scholler  :  Ber.  d.  chem.  Ges.,  7, 
1274;  Klinger  and  Masson:  Ann.  Chem.  (Liebig),  243,  193; 
252>  257;  Brown  and  Blaikie  :  J.  prakt.  Chem.  [2],  23,  395. 


204  ORGANIC   CHEMISTRY. 

3  grams  potassium  hydroxide. 

20  cc.  methyl  alcohol. 

0.8  gram  hydrogen  sulphide. 

13  grams  methyl  iodide. 

Put  in  a  200  cc.  flask  3  grams  of  potassium  hydroxide, 
and  dissolve  it  in  20  cc.  of  methyl  alcohol.  Weigh  on  a 
scale  sensitive  to  one-tenth  of  a  gram,  and  pass  into  the 
solution  0.8  gram  of  hydrogen  sulphide.  Filter  into  a 
loo  cc.  flask,  connect  with  an  effective  upright  con- 
denser, and  pour  in  through  the  latter  13  grams  (5^  cc.) 
of  methyl  iodide.  Warm  gently  till  the  reaction  begins, 
and  then  continue  to  boil  gently  for  half  an  hour.  Pour 
off  the  warm  solution  from  the  potassium  iodide  which 
separates.  On  cooling,  the  trimethylsulphine  iodide 
will  crystallize.  Pour  the  mother-liquors  back  into  the 
flask,  heat  to  boiling,  allow  to  cool  slightly,  and  pour 
off  as  before.  Recrystallize  the  trimethylsulphine  iodide 
once  or  twice  from  methyl  alcohol. 

Trimethylsulphine  iodide  crystallizes  in  prisms,  which 
are  easily  soluble  in  water,  more  difficulty  soluble  in 
alcohol.  The  study  of  the  sulphines  has  established, 
almost  beyond  question,  the  quadri valence  of  the  sul- 
phur in  them.  Their  study  has  also  rendered  it  proba- 
ble that  the  relation  of  the  groups  to  the  sulphur  is  such 
that  no  change  is  produced  in  the  molecule  when  two  of 
the  groups  exchange  places,  or,  as  usually  stated,  that 
the  four  valences  of  the  sulphur  atom  are  of  equal  value. 


X. 


Hydrocarbons, 

Hydrocarbons  may  be  prepared  by  distilling  salts  of 
acids  with  soda-lime  or  barium  hydroxide,  or  in  some 
cases,  with  sodium  methylate.  (Mai  :  Ber.  d.  chem. 
Ges.,  22,  2133.) 

RCO2Na  +  NaOH  =  RH  +  NaaCO3. 

A  second  method  consists  in  treating  halogen  deriva- 
tives of  the  hydrocarbons  with  sodium,  usually  in  ether- 
eal solution,  or  with  zinc  alkyl  compounds. 

RI  +  R'l  +  2Na  =  R—  R'  +  2NaI. 


2RI  +  Zn          =  2R—  R'  +  Znlf. 


These  methods  are  of  especial  value  for  the  determina- 
tion of  structure. 

A  somewhat  related  method  consists  in  treating  a 
mixture  of  an  aromatic  hydrocarbon,  and  an  alkyl  chlo- 
ride, bromide,  or  iodide  with  dry  aluminium  chloride 
(Friedel  and  Crafts).  This  method  of  synthesis  has 
already  been  illustrated  (see  71,  p.  184)  ,  but  it  loses  very 
much  in  value  from  the  fact  that  side  chains  of  aromatic  hy- 
drocarbons may  be  removed  by  the  action  of  aluminium 
chloride,  and  rearrangements  are  liable  to  result.  The 
reaction  has  never  been  satisfactorily  explained  in  all  of 
its  details,  but  it  is  evident  that  compounds  containing 
aluminium  are  formed  as  an  intermediate  product.  As 


206  ORGANIC   CHEMISTRY. 

an  illustration  of  the  reaction,  the  synthesis  of  triphenyl 
methane  may  be  given. 

C6H5\ 
3C6H6  +  CHC13  +  Aid,  =  C6H—  CH  +  3HC1  +  A1C13. 

C6H6/ 

Alcohols  are  usually  converted  into  unsaturated  hydro- 
carbons when  treated  with  concentrated  sulphuric  acid, 
(see  43,  p.  117)  or  zinc  chloride,  or  they  may  be  converted 
indirectly,  by  the  preparation  from  them  of  a  halogen 
alkyl,  and  treatment  of  the  latter  with  alcoholic  potash. 


H2S04  =  R"<<  +  H20. 


R"  +  H2S04. 

R<H  +  KOH  =  R"  +  KI  +  H'°- 

In  some  cases  quinoline  may  be  used  with  advantage 
in  place  of  alcoholic  potash.  (Baeyer:  Ber.  d.  chem. 
Ges.,25,  1840,  2122.) 

Monohalogen  derivatives  of  hydrocarbons  may  be  re- 
duced to  the  hydrocarbon,  the  reducing  agents  most 
commonly  used  being  concentrated  hydriodic  acid  ;  the 
copper  zinc  couple  in  the  presence  of  alcohol  or  water 
(Gladstone  and  Tribe  :  Ber.  d.  chem.  Ges.,  6,  202,  454, 
1136;  J.  Chem.  Soc.,  1884,  154)  ;  zinc  in  water  at  150°- 
160°  (Frankland  :  Ann.  Chem.  (L,iebig),  71,  203;  74, 
41);  and  aluminium  chloride  at  I2o°-i5o°  (Kohnlein  : 
Ber.  d.  chem  Ges.,  16,  560;  Kluge  :  Ann.  Chem.  (Lie- 
big),  282,  214).  The  iodides  are  more  suitable  than 
other  halogen  derivatives  for  these  reactions. 


HYDROCARBONS.  2OJ 

RI  +  HI    =    RH  +  I, 

2RI  +  2Zn  =  Zn<  ^+  ZnI2. 

Zn<|  +  2H2O  =  Zn(OH)a+  2RH. 

Dibrom  derivatives  with  the  halogen  atoms  com- 
bined with  adjacent  carbon  atoms,  lose  both  bromine 
atoms  with  the  formation  of  an  unsaturated  hydrocarbon 
on  treatment  with  sodium,  or  with  zinc  dust  and  acetic 
acid,  or  with  mercuric  iodide,  or  lead  iodide. 

Under  the  influence  of  condensing  agents,  such  as 
concentrated  sulphuric  acid,  zinc  chloride,  and  phos- 
phorus pentoxide,  or  pentasulphide,  ketones,  aldehydes, 
and  sometimes  other  compounds,  frequently  condense  to 
form  hydrocarbons.  In  this  way  mesitylene  is  formed 
from  acetone,  and  cymene  from  the  open  chain  aldehyde, 
geranial.  (Semmler:  Ber.  d.  chem.  Ges.,  23,  2965;  24, 
205.)  The  formation  of  cymene  from  camphor  is  prob- 
ably analogous  in  some  respects,  but  the  mechanism  of 
the  reaction  is  not  yet  satisfactorily  settled. 

A  great  variety  of  hydrocarbons,  especially  methane, 
defines,  acetylene,  and  aromatic  hydrocarbons,  are 
formed  by  heating  organic  compounds  to  high  tempera- 
tures. 

Aromatic  hydrocarbons  may  be  reduced  to  ' '  alicyclic ' ' 
compounds  by  reduction  with  hydriodic  acid  at  high 
temperatures,  or,  sometimes,  by  means  of  amyl  alcohol 
and  sodium.  Some  recent  work  by  Zelinsky  indicates, 
however,  that  hydriodic  acid  at  high  temperatures  some- 


2O8  ORGANIC   CHKMISTRY. 

times  transforms  a  hexamethylene  into  a  pentamethylene 
ring.     (Ber.  d.  chem.  Ges.,  30,  387.) 

C.H.+  6HI  =  C.H..  +  3I.. 
C10H8+4H  =  C.H..C.H.. 

Naphthalene.  Naphthalene 

tetrahydride. 

Ketones,  phenols,  alcohols,  and  in  some  cases  acids, 
may  be  reduced  to  hydrocarbons  by  heating  with  con- 
centrated hydriodic  acid,  or  hydriodic  acid  and  phos- 
phorus, usually  in  sealed  tubes. 

4HI  =      >CHa  +  2ls  +  H,0. 


Phenols,  and  sometimes  other  oxygen  compounds,  may 
be  reduced  to  hydrocarbons  by  distilling  over  heated 
zinc  dust,  usually  in  a  hard  glass  tube  in  a  combustion 
furnace. 

The  carbides  of  the  metals,  when  treated  with  water, 
or  with  acids,  give  hydrocarbons  which  differ  with  the 
metal.  Calcium  carbide  gives  acetylene,  aluminium 
carbide  gives  methane,  iron  carbide  chiefly  defines. 
(Moissan  :  Compt.  Rend.,  122,  1462.) 

Aromatic  amines  may  be  converted  into  hydrocarbons 
by  treatment  with  nitrous  acid  and  alcohol  (see  46,  p.  125)  . 
Sometimes,  however,  the  reaction  causes  the  replace- 
ment of  the  ainine  group  by  the  ethoxy  group,  C2H5O, 
instead  of  hydrogen.  (Remsen  and  his  co-workers  : 
Am.  Chem.  J.,  8,  243;  9,387;  IJ»  3*9  J  J5»  105  ;  19, 
163.) 


HYDROCARBONS.  2OQ 

82.  Preparation  of  a  Hydrocarbon  by  Distillation  of 
a  Salt  of  an  Acid  with  Soda-Lime.  —  Benzene,  C6H6. 
(Phen.) 

Literature.—  Mitscherlich  :  Ann.  Chem.  (Liebig),  9,  39  ;  Mar- 
ignac:  Ibid,  42,  217;  Wohler:  Ibid,  51,  146;  Berthelot  :  Ann. 
Chim.  Phys.  [4],  9,  469;  Hofmann  ;  Ber.  d.  chem.  Ges.,  4,  163; 
Baeyer  :  Ibid,  12,  1311  ;  V.  Meyer:  Ibid,  16,  1465. 

20  grams  benzoic  acid. 

40  grams  soda-lime. 

Mix  20  grams  of  benzoic  acid  with  40  grams  of  soda 
lime  by  grinding  together  in  a  mortar.  Put  the  mixture 
in  a  small  flask,  connect  with  a  condenser,  and  distil 
over  the  free  flame.  Separate  the  benzene  from  the 
water,  dry  it  with  calcium  chloride,  and  distil.  If  per- 
fectly dry  benzene  is  desired,  distil  it  a  second  time  over 
metallic  sodium.  Yield  8  to  9  grams. 

Benzene  solidifies  at  a  low  temperature,  and  melts  at 
5.42°.  It  boils  at  80.36°. 

This  method  of  preparation  is  no  longer  practically 
used,  but  it  was  of  very  great  importance  in  the  early 
study  of  the  aromatic  hydrocarbons,  and  illustrates  a 
method  very  general  in  its  application. 

83.  Preparation   of    a    Hydrocarbon    by    fleans  of 
Halogen     Compounds     and     Sodium.  —  Paraxylene, 

C.H4<  (i-4-Dimethylphen.) 


Literature.  —  Fittig,  Glinzer  :  Ann.  Chem.  (Liebig),  136,  303; 
Jannasch  :  Ibid,  171,  79;  V.  Meyer  :  Ber.  d.  chem.  Ges.,  3f  753  ; 
Jacobsen  ;  Ibid,  10,  1009,  1356;  Crafts:  Ztschr.  anal.  Chem., 
32,  243;  Compt.  Rend.,  114,  mo. 


210  ORGANIC   CHEMISTRY. 

35  grams  parabromtoluene. 

35  grams  methyl  iodide. 

12  grams  sodium  wire. 

100  cc.  ether. 

Press  into  a  200  cc.  flask  12  grams  of  sodium  in  the 
form  of  wire,  add  100  cc.  of  dry  ether  (see  n,  p.  51), 
and  place  the  flask  in  ice-water,  connect  with  an  upright 
condenser,  and  add  through  the  latter  a  mixture  of  35 
grams  of  parabromtoluene,  and  35  grams  of  methyl 
iodide.  Allow  the  mixture  to  stand  over  night,  or  till 
the  reaction  appears  to  be  complete.  Distil  off  the  ether 
on  the  water-bath,  and  distil  the  hydrocarbons  formed 
over  the  free  flame.  Remove  the  remainder  of  the  ether 
from  the  oil,  by  allowing  it  to  stand  in  a  crystallizing 
dish  for  half  an  hour  in  vacuo  over  sulphuric  acid.  Frac- 
tion repeatedly  from  a  small  distilling  bulb,  using  test- 
tubes  to  collect  the  distillates,  and  avoiding  loss,  as  far 
as  possible.  Collect  as  much  as  possible  of  the  paraxy- 
lene,  within  an  interval  of  2  to  3  degrees.  Cool  this 
portion  with  ice,  or  in  a  freezing  mixture,  and  pour  off 
the  part  which  does  not  solidify.  Yield  5  to  7  grams. 

Paraxylene  melts  at  15°,  boils  at  138°,  and  has  a  spe- 
cific gravity  of  0.880  at  o°.  It  is  oxidized  by  dilute 
nitric  acid  to  paratoluic  acid,  and  by  the  chromic  acid 
mixture  to  terephthalic  acid. 

84.  Synthesis  of  a  Hydrocarbon  by  Use  of  Aluminium 

CBH6\ 
Chloride.  — Triphenylmethane,  C6H5— CH.  (  Friedel 

C6HB/ 
and  Crafts'  reaction.) 


HYDROCARBONS.  211 

Literature  .— Kekule",  Franchimont :  Ber.  d.  chetn.  Ges.,  5, 
907  ;  Bottinger  :  Ibid,  12,  976  :  Linebarger  :  Am.  Chem.  J.,  13, 
557;  Hemilian  :  Ber.  d.  chem.  Ges.,  7,  1204;  Friedel,  Crafts: 
Ann.  Chim.  Phys,  [6],  1,489;  Compt.  Rend.,  84, 1450;  Anschiitz: 
Ann.  Chem.  (Liebig),  235,  208,  337 ;  K.  &  O.  Fischer:  Ibid,  194, 
352  ;  Allen,  Kollicker :  Ibid,  227,  107 ;  Biltz :  Ber.  d.  chem.  Ges., 
26,  1961. 

200  grams  benzene. 

40  grams  chloroform. 

20  grams  aluminium  chloride. 

Mix  200  grams  of  benzene  with  40  grams  of  chloro- 
form, add  some  fused  calcium  chloride,  and  allow  the 
mixture  to  stand  over  night.  Pour  off,  or  filter,  into  &dry 
flask,  connect  the  latter  with  an  upright  condenser  hav- 
ing a  calcium  chloride  tube,  which  is  bent  downward, 
connected  with  its  top.  Weigh  in  a  stoppered  prepara- 
tion tube  20  grams  of  aluminium  chloride,  best  freshly 
prepared.1  Add  from  the  tube  to  the  mixture  of  chloro- 
form and  benzene  3  to  4  grams  of  the  aluminium  chlo- 
ride. Shake  and  warm  until  the  reaction  begins  ;  after 
five  to  ten  minutes  add  a  second  portion  of  the  chloride, 
and  add  all  of  it  in  this  manner  in  about  thirty  minutes. 
Boil  the  mixture  gently  for  an  hour,  cool,  pour  carefully 
into  200  cc.  of  water,  stir,  transfer  to  a  separatory  fun- 
nel, shake,  and  separate  the  oil  from  the  water,  filter 
through  a  filter  moistened  with  benzene  to  remove 
water,  distil  off  the  benzene,  and  collect  in  fractions, 
below  100°,  ioo°-200°,  2OO°-3OO°.  Transfer  the  res- 

1  Aluminium  chloride  may  be  prepared  from  aluminium  turnings  and 
dry  hydrochloric  acid  gas.  (Stockhausen  and  Gattermann ;  Ber.  d.  chem. 
Ges.,  25,  3521.) 


212  ORGANIC    CHEMISTRY. 

idue  to  a  smaller  distilling  bulb  or  retort,  and  distil 
without  a  thermometer,  or  with  a  thermometer  filled 
with  nitrogen  under  pressure,  till  the  distillate  be- 
comes brown  and  viscous.  Crystallize  from  hot  ben- 
zene, obtaining  in  this  way  the  double  compound 
C19H16  +  C6H6,  which  crystallizes  in  colorless  crystals, 
that  melt  at  76°.  The  benzene  can  be  expelled  by 
warming  the  compound  on  the  water-bath,  and  the  tri- 
phenylmethane  may  be  crystallized  again  from  alcohol. 
Yield  25  to  30  grams,  if  the  aluminium  chloride  is  fresh. 

The  fraction  200°- 300°  consists  mainly  of  diphenyl- 
methane  (see  87,  p.  214). 

Triphenylmethane  crystallizes  in  rhombic  crystals, 
which  melt  at  92°.  It  boils  at  358°-359°.  It  is  easily 
soluble  in  ether,  chloroform,  and  hot  alcohol,  difficultly 
soluble  in  cold  alcohol. 

If  a  little  of  the  hydrocarbon  is  dissolved  in  cold  fum- 
ing nitric  acid,  and  the  solution  poured  into  water,  trini- 
trotriphenylmethane  is  obtained.  This  may  be  reduced 
to  the  amino  compound  by  zinc  dust  and  glacial  acetic 
acid.  The  amine  may  be  precipitated  from  the  filtered 
and  diluted  solution  by  ammonia.  If  the  amine  is 
heated  carefully  on  platinum  foil,  with  a  drop  of  con- 
centrated hydrochloric  acid,  the  red  color  of  the  chloride 
of  pararosaniline  will  be  noticed. 

85.  Preparation  of  a  Hydrocarbon  from  Camphor. 

rTT ^CH3  (i) 
— Cymene,  C6H4<^<^CH3(-     (/-Methyl-isopropyl 

phen.) 

Literature. — Gerhardt  and  Cahours  :  Ann.  Chem.  (Liebig),  38» 


HYDROCARBONS.  213 

71,  101,  205  ;  Gerhardt :  Ibid,  48, 234  ;  Dumas,  Delaland  :  Ibid,  38, 
342;  Pott:  Ber.  d.  chem.  Ges.,  2,  121;  Sylva :  Bull.  Soc.Chim., 
43*  32i  5  Jacobsen  :  Ber.  d.  chem.  Ges.,  12,  430;  Widman  :  Ibid, 
24,450;  Kekule":  Ibid,  6,  437;  Fittica  :  Ann.  Chem.  (L,iebig), 
172,  307;  Naudin  :  Bull.  Soc.  Chim.,  37,  in. 

30  grams  camphor. 

30  grams  phosphorus  pentoxide. 

Mix  intimately  in  a  flask  30  grams  of  camphor,  and  30 
grams  of  phosphorus  pentoxide.  Connect  with  a  con- 
denser, and  heat  in  an  oil-bath  as  long  as  cymene  distils. 
Add  to  the  cymene  a  little  phosphorus  pentoxide,  and 
boil  a  short  time  with  an  upright  condenser.  Pour  off, 
and  repeat  a  second  time.  Then  boil  the  cymene  with 
some  sodium  for  a  short  time,  using  an  upright  con- 
denser, and  finally  distil.  Yield  15  to  17  grams. 

Cymene  boils  at  175°,  and  has  a  specific  gravity  of 
0.8525  at  25°.  Potassium  permanganate  oxidizes  it  to 

OOTT  <^***         s 

hydroxypropylbenzoic  acid,  CflH4<CQ  H^  CH9   ;  the 

chromic  acid  mixture  to  terephthalic  acid  ;  dilute  nitric 
acid  to  paratoluic  acid. 

86.  Preparation  of  a  Hydrocarbon  by  a  Pyrogenic 

Reaction.— Diphenyl,  C6H5— C6H6. 

Literature. — Fittig :  Ann.  Chem.  (lyiebig),  xax,  363;  Berthe- 
lot:  Ztschr.  anal.  Chem.,  1866,  707:  Anschiitz,  Schultz :  Ann. 
Chem.  (Iviebig),  196,  48;  Aronheim :  Ber.  d.  chem.  Ges.,  9, 
1898;  Smith:  Ibid,  12,  722. 

200  cc.  benzene. 

Fill  the  central  portion  of  an  iron  tube,  2  cm.  in 
diameter,  and  about  50  cm.  longer  than  the  combustion 


214  ORGANIC   CHEMISTRY. 

furnace,  with  broken  pumice.  Connect  with  one  end  of 
the  tube,  by  means  of  a  perforated  cork,  a  tube  15  mm. 
in  diameter,  which  is  drawn  out  at  one  end  and  bent  at 
right  angles.  Into  the  wider  portion  of  the  tube,  which 
is  bent  upward,  fit  a  cork  bearing  a  separatory  funnel  in 
such  a  way  that  the  benzene  can  be  seen  as  it  drops  from 
the  end  of  the  funnel.  Raise  this  end  of  the  combustion 
furnace  about  two  inches  higher  than  the  other.  Con- 
nect the  other  end  of  the  iron  tube  with  a  small  con- 
denser, by  means  of  a  cork  and  glass  tube.  Drop  ben- 
zene from  the  separatory  funnel  at  the  rate  of  about  15 
drops  per  minute,  heating  the  central  portion  of  the  tube 
to  dull  redness.  When  200  cc.  of  benzene  have  been 
dropped  into  the  tube  in  this  manner,  distil  the  distillate, 
and  return  to  the  separatory  funnel  the  part  boiling  below 
120°.  Repeat  till  a  considerable  quantity  of  high  boil- 
ing products  has  been  obtained.  The  benzene  con- 
denses with  evolution  of  hydrogen. 

2C6H6=C6H6.C6H6  +  2H. 

Fraction  the  product,  and  crystallize  from  alcohol  the 
portion  boiling  from  235°-3OO°. 

Diphenyl  crystallizes  in  leaflets,  which  melt  at  70°. 
It  boils  at  254°,  and  dissolves  in  10  parts  of  alcohol  at  20°. 

87.  Preparation  of  a  Hydrocarbon  by  the  Reduction 
of  a  Ketone  with  Hydriodic  Acid. — Diphenylmethane, 
C6H6CHaC8H6. 

Literature.— Graebe :  Ber.  d.  chem.  Ges.,  7,  1624;  Zincke, 
Thorner:  Ber.  d.  chem.  Ges.,  10,  1473;  Staedel :  Ann.  Chem. 
(Liebig),  194.  307;  Zincke:  Ibid,  159.  374 ;  Friedcl,  Crafts: 


HYDROCARBONS.  215 

Ann.  Chem.  Phys.  [6],  i,  478;  E.  and  O.  Fischer  :  Ann.  Chem 
(Liebig),  194,  253. 

10  grams  benzophenone. 

12  grams  hydriodic  acid  (boiling-point  127°). 

2.2  grams  red  phosphorus. 

Put  in  a  tube  15  mm.  in  diameter,  and  with  walls  2 
mm.  thick,  10  grams  of  benzophenone,  12  grams  of  hy- 
driodic acid  (boiling-point  127°),  and  2.2  grams  of  red 
phosphorus.  Seal  carefully  (see  23,  p.  81),  and  heat  for 
6  hours  at  160°  in  a  bomb-oven.  Open  the  tube  care- 
fully by  softening  the  capillary  end  in  a  flame  till  it 
blows  out.  Cut  off  the  end  of  the  tube,  add  some  water 
and  ether  to  dissolve  the  hydrocarbon.  Separate  the 
ethereal  solution,  filter  it  from  the  red  phosphorus, 
distil  off  the  ether,  and  distil  the  diphenylmethane 
from  a  small  distilling  bulb.  Yield  8  to  8.5  grams. 

Diphenylmethane  melts  at  26°-27°,  and  boils  at  263°. 
It  is  easily  soluble  in  alcohol  and  ether.  It  has  a  specific 

26° 

gravity  of  i  .0008  at  —5- . 
4 

88.  Preparation  of  a  Hydrocarbon  by  Reduction  with 
Zinc  Dust. — Anthracene,  C14H10. 

Literature. — Dumas,  Laurent:  Ann.  Chem.  (Liebig),  5,  10  ; 
Lentny  :  Ber.  d.  chem.  Ges.,  10,  412;  xx,  1210;  Berthelot :  Ann. 
Chem.  (Liebig),  142,  254  ;  Behr,  Dorp  :  Ber.  d.  chem.  Ges.,  6, 
754;  Perkin,  Hodgkinson :  J.  Chem.  Soc.,  37,  726;  Schramm  : 
Ber.  d.  chem.  Ges.,  26, 1706  ;  Jackson:  Am.  Chem.  J.,  2,  384; 
Anschiitz:  Ann.  Chem.  (Liebig),  235, 165;  Graebe,  Liebermann  : 
Ann.  Chem.  (Liebig),  Supl.,  7,  297 ;  Baeyer :  Ann.  Chem.  (Lie- 
big),  140,  295  ;  Graebe  and  Liebermann :  Ber.  d.  chem.  Ges.,  i, 
49;  Landolt:  Ztschr.  Phys.  Chem.,  4,  369. 


2l6  ORGANIC   CHEMISTRY. 

i  gram  alizarin. 

Zinc  dust. 

Fill  a  combustion  tube  as  follows  :  Put  near  one  end 
a  loose  plug  of  asbestos,  then  5  cm.  of  zinc  dust,  then  a 
mixture  of  one  gram  of  alizarin,  with  30  grams  of  zinc 
dust,  then  about  30  cm.  of  a  mixture  of  zinc  dust  with 
about  £  its  weight  of  asbestos,  then  a  plug  of  asbestos, 
loosely  packed.  Rap  the  tube  on  the  table  to  give  a 
quite  free  channel  above  the  zinc  dust,  lay  the  tube  in 
the  combustion  furnace,  and  pass  hydrogen  from  the  end 
first  filled  till  the  air  is  expelled.  Heat  the  mixture  of 
asbestos  and  zinc  to  bright  redness,  then  the  mixture  of 
zinc  dust  and  alizarin,  slowly,  beginning  at  the  rear 
end,  continuing  a  slow  current  ~>f  hydrogen.  Crystallize 
the  anthracene,  which  sublimes  to  the  front,  cooler  part 
of  the  tube,  from  benzene  or  toluene,  and  determine  its 
melting-point.  Also  oxidize  a  part  of  it  with  chromic 
anhydride  in  glacial  acetic  acid,  and  determine  the 
melting-point  of  the  anthraquinone  (see  74,  p.  190). 

This  method  of  preparing  anthracene  is  of  great  his- 
torical significance,  as  it  led  Graebe  and  Liebermann  to 
the  discovery  of  the  character  of  alizarin,  and  so  indi- 
rectly led  to  its  synthetical  preparation. 


XL 


Miscellaneous  Compounds* 
86.  Skraup's  Synthesis  of  Quinoline.— 

CH     N 

CHX    C       CH 

II         I 
H       C       CH 


CH     CH 

Literature. — Gerhardt :  Ann.  Chem.  (Liebig),  42,  310  ;  44,  279; 
Baeyer :  Ber.  d.  chem.  Ges.,  12,  460,  1320 ;  Konigs :  Ibid,  12, 
453  *>  X3>  911 5  Wyschnegradsky  :  Ibid,  13,  911  ;  Skraup,  Monats- 
hefte,  i,  317 ;  2,  141 ;  J.  Walter :  J.  prakt.  Chem.,  49.  549 ; 
Knueppel :  Ber.  d.  chem.  Ges.,  29,  703 ;  Marckwald:  Ann.  Chem. 
(Liebig),  279,  3. 

24  grams  nitrobenzene. 

38  grams  aniline. 

100  grams  concentrated  sulphuric  acid. 

120  grams  glycerol. 

Put  in  a  liter  flask  the  mixture  given  above,  connect 
with  an  upright  condenser,  warm  slowly  till  the  reaction 
begins,  remove  the  flame  till  it  moderates,  and  then  boil 
for  two  hours.  Cool  somewhat,  add  100  cc.  of  water,  and 
distil  in  a  current  of  steam  (see  i,  p.  14)  as  long  as  the  dis- 
tillate smells  of  nitrobenzene.  Cool,  add  300  cc.  of 
caustic  soda  (3  cc.  =  i  gram),  and  distil  over  the  quin- 
oline  with  a  current  of  steam.  To  destroy  the  aniline 
which  is  present,  add  to  the  distillate  50  cc.  of  concen- 


2l8  ORGANIC   CHEMISTRY. 

trated  hydrochloric  acid,  and  then  a  strong  solution  of 
sodium  nitrite,  till  the  solution  smells  of  nitrous  acid. 
Heat  to  boiling  till  the  diazo  compound  is  decomposed  ; 
add  loo  cc.  of  caustic  soda,  and  distil  the  quinoline 
again  with  water  vapor.  Collect  the  quinoline  with  a 
little  ether,  distil  off  the  ether,  dry  the  residue  with  solid 
caustic  potash,  pour  off,  and  distil.  Yield  about  40 grams. 

Quinoline  boils  at  237°.  It  gives  an  orange-yellow, 
difficultly  soluble  precipitate  with  chloroplatinic  acid, 
(C.H,N),H,PtCl.. 

The  nitrobenzene  used  in  the  synthesis  acts  as  an  oxi- 
dizing agent,  and  Knueppel  has  shown  that  it  may  be 
replaced  with  advantage  by  arsenic  acid.  The  reaction  is 
C.H.NH.  +  C3H803+  O  =  C9H7N  +  4H2O. 

The  same  reaction  may  be  applied  to  a  great  many 
derivatives  of  benzene,  naphthalene  and  anthracene. 

90.  Preparation  of  a  Condensation  Product  from 
Phthalic  Anhydride. — Phenol  phthalein, 

OH 
C6H4(    /0-CO 

c     ,S 

C6H4/     XC6H4. 

OH 

Literature.— Baeyer :  Ann.  Chem.  (Liebig),  202,  68;  183,  i; 
Ber.  d.  chem.  Ges.,  9,  1230;  Knecht :  Ibid,  15,  1068;  Ann. 
Chem.  (Iviebig),  215,  83  :  Menschutkin  :  Ber.  d.  chem.  Ges.,  16, 
319:  H.  C.  Jones  and  Allen:  Am.  Chem.  J.,  18,  377. 

10  grams  phthalic  anhydride. 

8  grams  concentrated  sulphuric  acid. 

20  grams  phenol. 


MISCELLANEOUS   COMPOUNDS.  2 19 

Put  in  a  small  flask  10  grams  of  phthalic  anhydride, 
8  grams  of  concentrated  sulphuric  acid,  and  20  grams  of 
crystallized  phenol.  Heat  in  an  oil-bath,  with  a  ther- 
mometer in  the  mixture,  at  ii5°-i2O°  for  ten  hours. 
Pour  the  hot  mass  into  100  cc.  of  boiling  water,  and  boil 
till  the  odor  of  phenol  disappears,  filter  hot,  and  wash. 
Dissolve  the  residue  in  a  dilute  solution  of  sodium  hy- 
droxide, filter,  precipitate  with  acetic  acid  and  a  few 
drops  of  hydrochloric  acid,  and  allow  to  stand  for  twelve 
hours.  Dry  the  residue,  dissolve  it  in  6  parts  of  boiling 
alcohol,  add  one-half  its  weight  of  bone-black,  boil  for 
some  time,  filter,  and  wash  with  two  parts  of  hot 
alcohol.  Distil  off  two- thirds  of  the  alcohol,  and  add  a  very 
little  water.  Filter,  or  pour  off,  if  gummy  matters 
separate,  and  precipitate  the  phenol  phthalei'n  with  water, 
warming  for  a  few  minutes  to  cause  it  to  become  crystalline. 

The  crystalline  phenol  phthaleiu  melts  at  25o°-253°. 
Phenol-phthalem  forms  salts  with  alkalies,  which  are 
soluble  in  water  with  a  deep  red  color,  owing  to  their 
dissociation,  and  the  fact  that  the  free  ions  of  the  acid 
impart  to  solutions  a  red  color.  Phenol  phthalem  itself 
undergoes  almost  no  dissociation  in  solutions,  and  hence 
the  presence  of  free  hydrogen  ions,  caused  by  the  addi- 
tion of  an  acid,  even  of  carbonic  acid,  causes  the  disap- 
pearance of  the  color.  The  solutions  are  red  in  the 
presence  of  alkalies,  or  normal  carbonates,  but  colorless 
in  the  presence  of  bicarbonates,  or  free  acids.  Owing  to 
its  extreme  sensitiveness  to  even  weak  acids,  phenol 
phthalein  is  especially  suited  as  an  indicator  for  the 
titration  of  organic  acids. 


22O  ORGANIC   CHEMISTRY. 

By  heating  with  concentrated  sulphuric  acid  at  200°, 
phenol  phthalein  is  converted  into  oxyanthraquinone, 

C5H,<£°>C,H,OH. 

If  resorcin  is  used  in  place  of  phenol,  and  zinc  chloride 
is  used  as  a  condensing  agent,  (half  the  weight  of  the 
phthalic  anhydride) ,  the  temperature  being  raised  to 
till  the  mass  becomes  solid,  fluorescein, 
OH 


is  formed.     By  treating  with 


XOH 


bromine  in  an  alcoholic  solution,  this  is  converted  into 
tetrabromfluorescem  (eosin).  Kosin  and  other  similar 
compounds,  and  also  anthracene  derivatives  which  are 
obtained  from  these  compounds  by  heating  with  concen- 
trated sulphuric  acid  (see  above)  ,  are  used  as  dyestuffs. 

Compounds  of  the  fluorescein  type  are  only  formed 
when  the  hydroxyl  groups  of  the  phenol  are  in  the  meta 
position  and  the  third  meta  position  is  also  free. 

91.  Preparation  of  a  Derivative  of  Pyridine  by  Con- 
densation. —  Collidindicarboxyllic  ester, 

CH. 


C2H6CO9—  C         C—  C02C2H&. 

II          i 
C         C 

/    \^   \ 

CH3  N          CH8 


MISCELLANEOUS   COMPOUNDS.  221 

Literature.— Hantsch  :  Ann.  Chem.  (Liebig),  215,8  ;  Michael: 
Ibid,  225,  123  ;  Bamberger  :  Ber.  d.  chem.  Ges.,  24,  1763. 

20  grams  acetacetic  ester. 

5  grams  aldehyde  ammonia. 

10  grams  diliydrocollidindicarboxyllic  ester. 

Arsenious  anhydride. 

Nitric  acid  (sp.  gr.  1.30-1.33). 

Put  in  a  small  beaker  20  grams  of  acetacetic  ester,  and 
add  five  grams  of  aldehyde  ammonia.  Warm  gently  till 
the  reaction  begins,  remove  the  flame  for  a  short  time, 
and  then  boil,  with  stirring,  for  four  to  five  minutes  in 
all.  Add  a  little  alcohol,  and  allow  to  cool  till  the 
dihydrocollidindicarboxyllic  ester  crystallizes ;  filter, 
wash  once  with  dilute  alcohol,  and  then  with  water.  A 
small  amount  of  less  pure  ester  may  be  obtained  by 
diluting  the  filtrate. 

The  reaction  takes  place  in  some  such  manner  as  the 
following  : 

CH, 

C,H6— CO3— C  IOH  H|C!OH~H!CH— CO2C2H6 

II  : I       •        > 

CH  N;Ha  OjC 

/  \ 

CH3  CH3 

CH3 


CaH6CO2— C=C— CH— C02C,H6 

I  I  +  3H,0. 

C  H3— CH—  N=  C— CH3 

Put  10  grams  of  the  crude  ester  in  a  small  flask,  add 


222  ORGANIC    CHEMISTRY. 

20  cc.of  alcohol,  and  pass  in  a  rapid  stream  of  the  oxides 
of  nitrogen,  generated  by  warming  arsenious  oxide  with 
nitric  acid  of  sp.gr.  1.30-1. 33,  passing  the  gases  through 
an  empty  Drechsel  wash-bottle  to  condense  water.  Rub- 
ber connections  must  be  avoided  as  far  as  possible,  be- 
cause the  gas  attacks  them.  Continue  the  passage  of 
the  gas  till  a  drop  of  the  solution  dissolves  clear  in  dilute 
hydrochloric  acid.  Evaporate  the  alcohol  on  the  water- 
bath,  add  a  strong  solution  of  sodium  carbonate,  and 
take  up  the  collidindicarboxyllic  ester  with  ether.  Dry 
the  ethereal  solution  with  ignited  potassium  carbonate, 
and  distil  from  a  small  distilling  bulb.  Yield  7  to  8  grams. 

The  dihydro  ester  crystallizes  in  colorless  plates, 
which  melt  at  131°.  Its  solutions  show  a  beautiful  blue 
fluorescence.  It  is  almost  insoluble  in  water,  and  in 
dilute  acids,  difficultly  soluble  in  cold  alcohol,  easily 
soluble  in  hot  alcohol,  and  in  chloroform.  It  dissolves 
in  concentrated  hydrochloric  or  sulphuric  acid. 

Collidindicarboxyllic  diethyl  ester  boils  at  308°— 
310°.  It  is  easily  saponified  by  alcoholic  potash,  giving  a 
potassium  salt  difficultly  soluble  in  alcohol.  Collidine 
may  be  obtained  from  this  potassium  salt  by  mixing  it 
with  calcium  hydroxide  and  distilling. 

92.  Preparation  of  a  Pyrazolone  Derivative. — Anti- 
N-C6H6 

/     \ 

pyrine,CO         N— CH3         i-Phenyl-2,3-dimethyl-pyra- 

CH  —  C— C1I3 
zolone. 


MISCELLANEOUS   COMPOUNDS.  223 

Literature. — Knorr:  Ber.  d.  chem.  Ges.,  16,  2597;  17,  549, 
2037;  28,  706;  Ann.  chem.  (Liebig),  238,  137;  279,  188;  293,  i  ; 
Marckwald  ;  Ibid,  286,  350;  Nef:  Ibid,  266,  131;  287,  353;  Ben- 
der :  Ber.  d.  chem.  Ges.,  20,  2747 ;  Patents,  Knorr  ;  Ibid,  17, 
R,  149;  Meister,  Lucius,  and  Briining  :  Ibid,  18,  R,  725  ;  20,  R, 
609  ;  27,  R,  282. 

13  grams  acetacetic  ester. 

10  grams  phenyl  hydrazine. 

10  grams  i-phenyl-3-methylpyrazolone. 

10  grams  methyl  iodide. 

10  grains  methyl  alcohol. 

Putin  a  flask  13  grams  of  acetacetic  ester,  add  10  grams 
of  phenyl  hydrazine,  and  heat  on  the  water-bath  for  two 
hours,  or  till  a  drop  of  the  mixture  becomes  perfectly 
solid  on  treating  with  a  little  ether  on  a  watch-glass. 
Pour  the  warm  mass,  with  stirring,  into  a  small  amount 
of  ether,  filter,  wash  with  ether,  and  dry. 

The  acetacetic  ester  and  phenyl  hydrazine  condense 
at  first  with  the  formation  of  a  hydrazide, 

CH3 
\ 
C— NH— NH— C6H&, 

II 
C3HB— CO2CH 

and  this,  on  heating,  condenses,  with  loss  of  alcohol,  to 

C6HB 

N 

/     \ 
i-phenyl-3-methylpyrazolone,      CO       NH.       In  work- 

HC   =   C— CH3 


224  ORGANIC   CHEMISTRY. 

ing  with  larger  amounts  it  may  be  desirable  to  separate 
the  water  formed  by  the  first  condensation,  as  Knorr 
suggests,  but  the  directions  given  are  satisfactory  for 
small  amounts.  The  phenylmethylpyrazolone  melts  at 
127°,  is  almost  insoluble  in  cold  water,  ether,  andligroin, 
more  easily  soluble  in  hot  water,  and  very  easily  soluble 
in  alcohol.  It  dissolves  both  in  acids  and  in  alkalies. 

Put  in  a  thick- walled  tube  10  grams  of  the  phenyl 
methylpyrazolone,  10  grams  of  methyl  iodide,  and  10 
grams  of  methyl  alcohol.  Seal  carefully,  (see  23,  p.  81), 
and  heat  in  a  bomb-oven,  or  in  an  iron  tube  (to  guard 
against  explosion)  in  a  water-bath  for  two  to  three  hours. 
Cool,  open  the  capillary  by  softening  in  a  flame,  cut  off  the 
end,  transfer  the  contents  of  the  tube  to  a  beaker,  add  a 
small  amount  of  a  solution  of  sulphur  dioxide,  and  some 
water,  boil  to  expel  the  alcohol,  cool,  add  sodium 
hydroxide  in  slight  excess,  and  extract  several  times 
with  a  small  amount  of  chloroform.  Distil  off  the  chlo- 
roform, and  crystallize  the  antipyrine  from  toluene. 
The  yields  are  nearly  quantitative,  except  for  the  loss 
in  manipulations. 

Antipyrine  crystallizes  in  leaflets,  which  melt  at  116°. 
It  is  easily  soluble  in  water,  alcohol,  benzene,  and  chlo- 
roform, difficultly  soluble  in  ether  and  ligroin.  The 
aqueous  solution  is  colored  red  by  ferric  chloride. 
Dilute  solutions  give  a  bluish-green  color  with  nitrous 
acid.  CH— CH 

II         II 
93.  Thiophen.—     CH     CH. 

\S 

s 


MISCEUvANKOUS   COMPOUNDS.  225 

Literature. — V.  Meyer:  Ber.  d.  chem.  Ges.,  16,  1465,  1471; 
Ibid,  17,  2641  ;  18,  217 ;  V.  Meyer  and  Sandmeyer :  Ibid,  16, 
2176 ;  Volhard  and  Erdmann  :  Ibid,  18,  454  ;  Schulze  :  Ibid,  18, 
497  ;  Paal  and  Tafel :  Ibid,  18,  456. 

109  grams  phosphorus  trisulphide.1 
loo  grams  dry  sodium  succinate. 

Powder  finely  and  mix  together  100  grams  of  phos- 
phorus trisulphide,  and  100  grams  of  sodium  succinate, 
dried  thoroughly  at  140°.  Put  the  mixture  in  a  flask  or 
non-tubulated  retort,  which  should  be  filled  only  half 
full.  Connect  with  a  condenser,  which  has  a  distilling 
bulb  tightly  fastened  to  its  lower  end  and  surrounded  with 
a  freezing  mixture.  From  the  side  tube  of  the  dis- 
tilling bulb  connect  tubes  leading  out  of  doors  or  to  the 
chimney.  Heat  till  the  reaction  begins,  and  then  allow 
it  to  proceed  of  itself  till  completed. 

Distil  the  thiophen  from  the  water-bath,  wash  it  with 
a  solution  of  caustic  soda,  dry  it  with  sodium,  and  distil. 

Thiophen  is  a  mobile,  colorless  liquid,  which  boils  at 
84'',  and  has  a  specific  gravity  of  1.062  at  23°.  On 
warming  a  minute  portion  of  it  with  isatine  and  concen- 
trated sulphuric  acid,  a  bluish-green  color  is  produced. 
This  reaction  is  used  to  detect  thiophen  in  benzene. 

94.  Orthobenzoylbenzoic  Acid,  C6H4<£Q~C«H«' 
Diphenylmethanonmethyllic  (2)  acid. 

1  The  phosphorus  trisulphide  can  be  prepared  by  melting  together,  in  a 
Hessian  crucible,  the  theoretical  amounts  of  dry  red  phosphorus  and  sul- 
phur. The  sodium  succinate  can  be  obtained  by  neutralizing  succinic  acid 
with  a  strong  solution  of  sodium  carbonate  or  caustic  soda,  and  evaporating 
the  solution  to  dryness. 


226  ORGANIC    CHEMISTRY. 

Literature  —  Plaskuda,  Zincke  :  Ber.  d.  chem.  Ges.,  6,  707  ; 
Behr,  Dorp:  Ibid,  7,  17  ;  Friedel,  Crafts  :  Ann.  Chim.  Phys.  [6], 
14,446;  Pechmann  :  Ber.  d.  chem.  Ges.,  13,  1612;  Graebe  and 
Uhlmann:  Ann.  Chem.  (Liebig),  291,  8. 

20  grams  phthalic  anhydride. 

100  cc.  benzene  (free  from  thiophen). 

30  grams  aluminium  chloride. 

In  a  300  cc.  flask  put  20  grams  of  phthalic  anhydride, 
and  loo  cc.  of  benzene,  free  from  thiophen.  Warm  till 
the  anhydride  dissolves,  and  cool.  Connect  with  an  up- 
right condenser,  and  add,  in  portions  of  3-5  grams,  30 
grams  of  dry,  powdered  aluminium  chloride.  If  the  re- 
action becomes  too  violent,  cool  the  flask  with  water. 
The  whole  of  the  chloride  may  be  added  in  ten  to  fifteen 
minutes.  Warm  on  the  water-bath  for  two  hours.  Cool, 
add  carefully,  through  the  condenser,  80  cc.  of  cold 
water,  and  20  cc.  of  concentrated  hydrochloric  acid. 
Distil  off  the  benzene  with  water  vapor,  cool,  filter,  and 
wash.  Dissolve  the  acid  in  80  cc.  of  a  lo-per  cent,  solu- 
tion of  sodium  carbonate,  filter,  and  pour  into  a  mixture 
of  35  cc.  concentrated  hydrochloric  acid,  4occ.of  water, 
and  some  pieces  of  ice.  Filter,  and  suck  dry.  In  order 

to  obtain  the  dry  0-benzoylbenzoic  aci  d,  CgR^^T..  6    B' 


this  product  may  be  dried  at  125°-!  30°,  or  it  may  be  dis- 
solved in  warm  chloroform,  separated  from  the  water 
swimming  on  top,  the  solution  dried  with  calcium  chlo. 
ride,  and  the  chloroform  distilled.  The  dry  acid  may 
be  crystallized  from  xylene.  Yield  22  to  23  grams. 
Orthobenzoylbenzoic  acid  crystallizes  from  water  in 


MISCELLANEOUS   COMPOUNDS.  227 

long  needles,  which  contain  water  of  crystallization  and 
melt  at  85°-87°.  It  is  moderately  soluble  in  hot  water, 
difficultly  soluble  in  cold  water. 

When  the  dry  acid  is  heated  to  200°,  for  an  hour,  with 
an  equal  weight  of  phosphorus  pentachloride,  it  is  con- 
verted almost  quantitatively  into  anthraquinone. 

95.  Phenyl  Cyanide,  CBH5CN.     Benzonitrile. 

Literature. — Laurent,  Gerhardt :  Jsb.  d.  chem.,  1849,  327; 
Wohler  :  Ann.  Chem.  (Liebig),  192,  362 ;  Henry  ;  Ber.  d.  chem. 
Ges.,  2,  307 ;  Letts  :  Ibid,  5,  673 ;  Merz  ;  Ztschr.  chem.,  1868, 
33;  Merz,  Weith  :  Ber.  d.  chem.  Ges.,  8,  918;  10,  749;  Lach: 
Ibid,  17,  1571 ;  Sandmeyer :  Ibid,  17,  2653. 

15  grams  benzoyl  chloride. 

60  cc.  ammonia  (sp.  gr.  0.96). 

10  grams  benzamide. 

15  grams  phosphorus  pentoxide. 

Put  in  a  flask  15  grams  of  benzoyl  chloride,  add  60  cc. 
of  ammonia  (10  per  cent.),  and  shake  vigorously  till  the 
chloride  dissolves,  which  should  take  only  a  minute  or 
two.  Cool  at  once  and  thoroughly.  Filter  off  the 
benzamide  which  separates,  wash  it  till  free  from  am- 
monium chloride,  and  dry  in  the  air  or  on  the  water- 
bath,  ii  grams  of  pure  benzamide  should  be  obtained. 

Put  in  a  small  distilling  bulb  10  grams  of  benzamide, 
and  15  grams  of  phosphorus  pentoxide,  and  mix  as 
thoroughly  as  possible  by  shaking.  Heat  in  an  oil-bath 
at  220°-240°  as  long  as  phenyl  cyanide  distils  over.  A 
condenser  is  not  necessary,  but  the  cyanide  may  be  col- 
lected in  a  small  flask  or  test-tube  as  it  distils.  Yield  6 
to  7  grams. 


228  ORGANIC   CHEMISTRY. 

Most  amides  lose  water  when  heated  with  phosphorus 
pentoxide,  and  are  converted  into  the  corresponding 
cyanides  or  nitriles. 

Benzamide  crystallizes  in  monoclinic  plates,  or  in  leaf- 
lets which  melt  at  128°.  It  is  difficultly  soluble  in  cold 
water,  easily  soluble  in  alcohol. 

Phenyl  cyanide  is  a  colorless  oil  which  solidifies  in  a 
freezing  mixture  of  ether  and  solid  carbon  dioxide,  and 
melts  at  — 17°.  It  boils  at  190.7°,  and  has  a  specific 
gravity  of  1.0084  at  16.8°. 

96.  Zinc  Ethyl,  Zn<£2JJ6. 
^A 

Literature — Frankland  ;  Ann.  Chem.  (Liebig),  95,  28:  Beil- 
stein,  Rieth:  Ibid,  123,245;  126,  248;  Rathke  :  Ibid,  152,  220: 
Gladstone,  Tribe:  Ber.  d.  chem.  Ges.,  6,  200-  J.  Chem.  Soc., 
35,  569 ;  Kaulfuss :  Ber.  d.  chem.  Ges.,  20,  3104  ;  Haase ;  Ibid, 
26,  1053 ;  Arthur  Lachman  :  Am.  Chem.  J.,  19,  410. 

1 8  grams  powdered  zinc. 

2  grams  reduced  copper. 

20  grams  ethyl  iodide. 

Put  in  50  cc.  round-bottomed  flask  18  grams  of  pow- 
dered zinc1,  and  2  grams  of  copper  powder,  obtained  by 
reducing  fine  copper  oxide  in  hydrogen  at  a  low  tem- 
perature. Close  the  flask  with  a  cork  having  a  small 
glass  tube  through  it.  Heat  gently  over  a  free  flame, 
turning  all  the  time  till  the  mass  becomes  gray  and  loses 
its  luster,  but  not  till  there  is  any  sign  of  fusion.  Seal 
the  glass  tube,  and  allow  to  cool. 

1  Baker  and  Adamson's  zinc,  powdered  to  pass  a  30  mesh  sieve,  answers 
well  for  this  purpose.  Arthur  I/achman  (loc.  cit.)  prepares  a  zinc-copper 
couple  by  mixing  zinc  dust  with  one-eighth  of  its  weight  of  fine  copper  oxide 
and  reducing  in  a  current  of  hydrogen  at  a  dull  red  heat. 


MISCELLANEOUS   COMPOUNDS.  22Q 

Bend  a  glass  tube,  of  such  size  and  length  as  to  replace 
the  inner  tube  of  a  small  Liebig  condenser,  at  an  angle 
of  135°  near  the  end.  Insert  the  tube  in  the  mantle  of 
the  condenser,  clamp  the  latter  at  an  angle  of  45°  with 
the  horizontal,  and  connect  the  flask  containing  the  zinc- 
copper  couple  to  the  lower  end  of  the  bent  tube,  with 
a  tightly  fitting  cork.  Pour  in  through  the  condenser 
20  grams  of  ethyl  iodide.  Place  a  test-tube,  large 
enough  to  allow  a  small  glass  tube  to  pass  into  it  beside 
the  condenser  tube,  over  the  upper  end  of  the  condenser, 
nearly  closing  the  mouth  of  the  test-tube  with  a  cork 
ring  or  with  paper.  Pass  into  the  test-tube  a  slow  cur- 
rent of  carbon  dioxide,  and  heat  the  flask  containing  the 
ethyl  iodide  and  zinc-copper  couple  on  the  water-bath 
as  long  as  ethyl  iodide  continues  to  distil  and  run  back, 
usually  only  a  short  time.  Then  turn  the  condenser  in 
such  a  way  that  the  main  tube  of  the  condenser  slants 
downward,  and  distil  off  the  zinc  ethyl  carefully  with  a 
free  flame,  continuing  the  current  of  carbon  dioxide 
through  the  test-tube. 

By  heating  on  the  water-bath,  the  ethyl  iodide  reacts 

O  TT 
with  the  zinc,  forming  ethyl  zinc  iodide,   Zn<Cj2    B.  On 

heating  to  a  higher  temperature,  zinc  ethyl  is  formed. 


On  account  of  its  spontaneous  inflammability  on  coming 
to  the  air,  very  great  care  must  be  exercised  in  working 
with  zinc  ethyl,  and  it  must  be  kept  in  sealed  tubes,  and 
in  a  fire-proof  case.  Small  bulbs  can  be  filled  with  the 


230  ORGANIC   CHKMISTRY. 

substance  by  preparing  them  with  a  small  capillary  tube 
on  both  sides,  filling  them  with  carbon  dioxide,  drawing 
the  zinc  ethyl  up  into  the  bulb,  (if  drawn  by  suction 
with  the  mouth  a  large  bulb  of  some  sort  should  be  in- 
terposed), and  sealing  the  tube  above  the  bulb  with  a 
blow-pipe. 

Zinc  ethyl  boils  at  118°,  and  has  a  specific  gravity  of 
1.182  at  1 8°.  It  takes  fire  spontaneously  in  the  air,  or 
in  chlorine,  and  decomposes  violently  with  water,  giving 
zinc  hydroxide  and  ethane. 


&  CALlS^ 

CHAFTKR  XII. 


Qualitative  Examination  of  Carbon  Compounds* 

Because  of  the  very  great  number  of  carbon  com- 
pounds, it  is  impossible  to  give  any  scheme  for  qualita- 
tive examination  which  is  at  all  general  in  its  applica- 
tion. In  dealing  with  an  unknown  substance  or  mix- 
ture, the  first  attempt  should  be  to  determine  what  ele- 
ments other  than  carbon  are  present,  and  whether  the 
substance  is  a  single  one  or  a  mixture.  For  the  latter 
purpose  boiling-points  and  melting-points  are  most  gen- 
erally applicable,  substances  with  a  constant  boiling- 
point,  and  with  a  sharp  melting-point,  being  usually 
pure,  though  there  are  some  exceptions.  For  the  de- 
termination of  what  elements,  other  than  carbon  and 
hydrogen,  are  present,  the  method  most  generally  appli- 
cable consists  in  heating  about  o.  i  gram  of  the  substance 
with  i  cc.  of  fuming  nitric  acid  (sp.  gr.  1.48  at  least)  at 
20O°-3OO°  for  two  hours,  in  a  sealed  tube  having  a  ca- 
pacity of  20  to  30  cc.  The  tube  must  be  heavy- walled 
and  carefully  sealed,  with  a  capillary  at  one  end.  When 
cold,  this  end  is  softened  carefully  in  the  flame  till  the 
gases  blow  out.  The  nitric  acid  will  contain  sulphur, 
phosphorus,  and  arsenic  in  the  form  of  their  respective 
acids,  chlorine,  and  bromine  partly  in  the  form  of  hydro- 
chloric and  hydrobromic  acids,  and  partly  free,  iodine  in 
the  form  of  iodic  (not  hydriodic)  acid,  and  metallic 
elements  in  the  form  of  nitrates.  All  of  these  may  be  de- 


232  ORGANIC   CHEMISTRY. 

tected,  when  present,  by  means  of  the  usual  qualitative 
tests  of  inorganic  chemistry. 

Another  method,  which  is  much  quicker  and  almost 
as  general  in  its  application  for  non-metallic  elements, 
consists  in  heating  with  metallic  sodium.  Put  in  a 
short,  dry  tube  of  hard  glass,  about  •£$  gram  of  clean 
sodium.  Heat  quickly  over  a  small  flame  till  part  of 
the  sodium  is  converted  into  vapor,  and  drop  straight 
down  into  the  tube  one  or  two  drops  of  the  substance,  if 
a  liquid,  or  a  corresponding  amount  of  a  solid.  Allow 
to  cool,  add  a  little  alcohol  to  dissolve  unchanged 
sodium,  then  a  fewcc.  of  water,  and  filter.  The  solution 
may  be  tested  for  various  elements  as  follows  : 

Sulphur,  with  a  silver  coin,  with  a  solution  of  sodium 
nitroprusside,  or  with  a  solution  of  lead  acetate  in 
sodium  hydroxide. 

Cyanides  (in  absence  of  sulphur),  by  warming  with 
sodium  hydroxide  and  a  small  amount  of  a  mixture  of 
ferrous  and  ferric  salts,  and  subsequent  acidification 
with  hydrochloric  acid,  when  prussian  blue  will  be 
formed,  if  nitrogen  was  present  in  the  original  sub- 
stance. In  some  cases  metallic  potassium  reacts  more 
readily  than  sodium  for  the  detection  of  nitrogen. 

Chlorine,  with  nitric  acid  and  silver  nitrate ;  if  sul- 
phur or  nitrogen  are  present,  it  is  necessary  to  boil  with 
nitric  acid  before  adding  the  silver  nitrate. 

Bromine  and  iodine,  with  hydrochloric  acid,  carbon 
bisulphide  and  chlorine  water,  or  potassium  nitrite  for 
iodine. 


CARBON    COMPOUNDS.  233 

Sulphur  and  nitrogen  together  will  form  a  sulpho- 
cyanide,  which  gives  a  red  color  with  ferric  chloride 
after  acidifying  with  hydrochloric  acid. 

The  following  special  tests  are  also  frequently  useful : 

Nitrogen. — Many  nitrogenous  compounds,  but  not 
all  (especially  not  nitro  compounds),  give  ammonia 
when  heated  in  a  small  tube  with  soda  lime.  The  am- 
monia is  best  detected  by  means  of  moist,  reddened  lit- 
mus paper  in  the  mouth  of  the  tube. 

Halogens. — Make  a  small  loop  in  the  end  of  a  copper 
wire,  and  oxidize  it  by  holding  it  in  the  outer  edge  of  a 
Bunsen  flame.  Cool,  dip  in  a  little  of  the  substance  to 
be  tested,  and  hold  in  the  flame.  The  latter  will  be 
tinged  green  if  a  halogen  is  present.  Halogens  may 
also  be  detected  by  igniting  the  substance  with  pure 
quicklime  in  a  tube  of  hard  glass,  dissolving  the  residue 
in  nitric  acid  and  testing  in  the  usual  manner.  In  many 
cases,  also,  by  heating  with  sodium  carbonate  till  car- 
bonization takes  place,  adding  some  potassium  nitrate, 
and  heating  again  till  white,  dissolving  in  water,  and 
testing  with  nitric  acid  and  silver  nitrate.  Kastle  and 
Beatty,  (Am.  Chem.  J.,  19, 412),  recommend  to  heat  o.i 
gram  of  the  substance  to  be  tested  with  0.5  gram  of  a 
mixture  of  copper  and  silver  nitrates  in  a  test-tube. 
When  cold,  dilute  sulphuric  acid  and  zinc  are  added, 
after  five  or  ten  minutes  the  solution  is  filtered  and  the 
filtrate  tested  with  silver  nitrate  and  nitric  acid.  With 
volatile  substances  a  slight  modification  is  necessary. 

Having  determined  what  elements  are  present,  and,  if 
possible,  whether  the  substance  under  examination  is  a 


234  ORGANIC    CHEMISTRY. 

single  compound  or  a  mixture,  and,  in  case  of  mixtures, 
having,  if  possible,  separated  the  constituents,  the  remain- 
der of  the  examination  will  consist  mainly  in  the  en- 
deavor to  obtain  some  idea  of  the  nature  of  the  sub- 
stance, and  then  to  identify  it  as  agreeing  entirely  in  its 
properties  with  some  body  described  in  the  text-books 
or  hand-books  on  organic  chemistry.  The  following 
general  principles  will  be  of  service  : 

Acids  are,  in  most  cases,  sufficiently  soluble  in  water 
to  redden  blue  litmus,  and  in  almost  all  cases  they  are 
soluble  in  ammonia  or  sodium  hydroxide,  and  decom- 
pose sodium  carbonate  with  evolution  of  carbon  dioxide. 
Polybasic  acids  are  usually  more  soluble  in  water  than 
monobasic  ones,  and  the  solubility  usually  decreases  with 
an  increase  of  molecular  weight.  The  lead  and  silver  salts 
of  many  acids  are  difficultly  soluble,  and  may  be  ob- 
tained by  precipitation  from  solutions  of  sodium  or  am- 
monium salts.  The  calcium  salts  of  bibasic  acids  are 
often  difficultly  soluble.  The  bodies  most  liable  to  be 
mistaken  for  acids  are  phenols,  some  esters  of  ketonic 
acids,  and  acid  amides  and  imides,  these  compounds  be- 
ing, in  many  cases,  soluble  in  alkalies,  and  precipitated 
again  by  acids. 

Esters  are  identified  by  saponification  by  boiling  with 
alkalies  or  acids,  and  subsequent  determination  of  the 
alcohol  and  acid  from  which  they  are  derived. 

Amides,  imides  and  nitriles  are  also  identified  by 
boiling  with  alkalies  or  acids,  which  decompose  them 
with  formation  of  ammonia.  The  derivatives  of  differ- 


CARBON    COMPOUNDS.  235 

ent  acids  differ  very  greatly,  of  course,  in  the  ease  with 
which  they  are  saponified. 

Halogen  derivatives  of  hydrocarbons  are  universally 
insoluble  in  water.  Many  of  them  are  decomposed  by 
alcoholic  potash  with  formation  of  unsaturated  hydro- 
carbons, but  the  halogen  atoms  in  the  nucleus  of  benzene 
derivatives  usually  react  with  difficulty,  if  at  all. 

Nitro  compounds  may  be  reduced  to  amines  by  tin 
and  hydrochloric  acid.  Most  nitro  compounds  give  yel- 
low solutions  on  warming  with  alcoholic  potash.  The 
nitro  compounds  themselves  are  insoluble,  or  very  diffi- 
cultly soluble  in  water.  They  evolve  no  ammonia,  or 
very  little  on  warming  with  soda-lime. 

Amines  are  best  characterized  by  the  formation  of 
salts  with  acids.  The  salts  with  chloroplatinic  (H3Pt 
C16)  and  chlorauric  (HAuClJ  acids  are  frequently, 
though  by  no  means  always,  difficultly  soluble  and  char- 
acteristic. 

Aliphatic  amines  and  aromatic  amines  with  the  amino 
group  in  the  side  chain,  react  strongly  alkaline  with 
litmus.  Aromatic  amines,  with  the  amino  group  in  the 
nucleus,  do  not  turn  red  litmus  blue.  They  form  well 
defined  salts,  however.  To  distinguish  primary,  sec- 
ondary and  tertiary  amines,  see  p.  85.  Another  method 
of  distinguishing  them  consists  in  treatment  with 
nitrous  acid.  Primary  amines  form  alcohols,  or  unsat- 
urated hydrocarbons,  or  diazo  bodies  which  decompose 
with  water  to  form  phenols.  Secondary  amines  form 
nitroso  amines,  which,  on  solution  in  phenol,  treat- 
ment with  a  little  concentrated  sulphuric  acid,  and 


236  ORGANIC   CHEMISTRY. 

subsequent  dilution,  and  neutralization  with  caustic  pot- 
ash, give  a  blue  color  .  (Liebertnann's  reaction  :  Ber. 
d.  chetn.  Ges.,  7,  248;  Baeyer  ;  Ibid,  7,  966.)  The  re- 
action appears  to  be  due  to  the  formation  of  a  nitrosophe- 
nol  by  the  action  of  the  nitrosoamine,  and  a  subsequent 
condensation  under  the  influence  of  the  sulphuric  acid. 
Tertiary  amines  do  not  react  with  nitrous  acid. 

When  a  primary  amine  is  warmed  with  a  little  chloro- 
form and  alcoholic  potash,  an  isonitrile  is  formed,  which 
can  be  recognized  by  its  penetrating  and  exceedingly 
disagreeable  odor.  (Hofmann.) 


3KOH  =  R—  N= 


When  a  primary  amine  is  treated  with  a  little  carbon 
disulphide,  dissolved  in  alcohol  or  ether,  a  salt  of  an 
alkyl  thiocarbamic  acid  is  formed. 


If,  after  evaporating  part  of  the  alcohol,  the  solution 
is  warmed  with  not  too  much  mercuric  chloride,  or  bet- 
ter with  ferric  chloride,  a  mercuric  salt  of  the  thiocarbamic 
acid  is  at  first  formed,  and  this  is  then  decomposed  with 
the  formation  of  an  isosulphocyanide  (mustard  oil)  with 
a  characteristic  odor. 


or 


R—  NH—  C—  SHRNH2+2FeCl8  =  R—  N=C=S  + 
RNH2HC1  +  HC1  +  S  +  2FeCl2. 


CARBON    COMPOUNDS.  237 

Hydrazo,  azo,  diazo  bodies,  etc.,  may  usually  be 
recognized  by  their  characteristic  properties,  as  given  in 
the  chapter  on  these  substances  and  in  larger  works. 

Alcohols,  phenols,  and  all  bodies  containing  hydroxyl, 
react  with  sodium  with  the  evolution  of  hydrogen. 
Some  bodies  not  usually  supposed  to  contain  hydroxyl, 
as  aldehydes  and  some  ketones,  react  in  the  same  man- 
ner, however.  The  formation  of  an  acetyl  or  benzoyl 
derivative  (most  easily  by  the  Schotten-Baumann  reac- 
tion when  it  can  be  applied,  pp.  86  and  91),  is  especially 
characteristic  of  alcohols  and  phenols.  It  must  be  re- 
membered, however,  that  primary  and  secondary  amines 
show  a  similar  reaction. 

Methyl  or  ethyl  alcohol  may  be  detected  in  dilute 
aqueous  solutions,  as  follows  :  Distil  10  to  20  cc.  from 
1 00—200  cc.  of  the  solution.  Put  the  distillate  in  a 
smaller  bulb,  and  distil  4  to  6  cc.  To  this  distillate,  in  a 
test-tube,  add  dry  potassium  carbonate  till  the  alcohol 
separates  on  top.  Transfer  the  upper  layer  to  a  small 
distilling  bulb  by  means  of  a  pipette,  and  determine  its 
boiling-point,  boiling  it  with  a  very  small  flame,  and 
using  a  thermometer  with  as  small  a  bulb  as  possible. 
Bthyl  alcohol  may  be  identified  in  this  manner  in  100 
cc.  of  a  one  per  cent,  solution. 

Phenols,  and  hydroxy  acids  in  which  the  hydroxyl  is 
ortho  to  the  carboxyl,  give  characteristic  color  reactions 
with  ferric  chloride  in  aqueous,  and  sometimes  in  alco- 
holic solutions.  Phenols  dissolve  in  alkalies  with  the 
formation  of  unstable  salts.  The  alkaline  solutions  of 


238  ORGANIC   CHEMISTRY. 

phenols  are  usually  very  sensitive  to  oxidation,  and  to 
the  action  of  the  air. 

Aldehydes  and  ketones  are  usually  most  easily 
recognized  by  the  action  of  phenyl  hydrazine  in  dilute 
acetic  acid  solution  (see  75,  p.  191).  The  formation  of  com- 
pounds with  acid  sodium  or  potassium  sulphite  (see 
72,  p.  1 88)  hydroxylamine,  and  semi-carbazine  may  also 
be  used  for  purposes  of  identification  (see  76  and  77,  p. 
192  and  193).  Aldehydes  redden  instantly  a  very  dilute 
cold  solution  of  a  fuchsine  salt,  which  has  been  decol 
orized  by  sulphurous  acid  (Caro).  Aldehydes  reduce  a 
cold,  ammoniacal  solution  of  silver  nitrate  (see  70, 
p.  184).  (Tollens.) 

Sulphonic  acids  are  usually  easily  soluble,  and  the 
salts  are  mostly  soluble,  and  many  of  them  crystallize 
well.  The  most  important  reaction  of  sulphonic  acids 
for  purposes  of  identification  are  the  formation  of  sul- 
phonamides  (see  25,  p.  83),  the  formation  of  phenols  by  fu- 
sion with  caustic  potash  (see  67,  p.  172) ,  the  formation  of 
nitriles  by  distillation  of  a  sodium  or  potassium  salt  with 
potassium  cyanide,  of  acids  by  fusion  with  sodium  for- 
mate, and  the  regeneration  of  the  original  hydrocarbon 
by  heating  in  a  sealed  tube  with  concentrated  hydro- 
chloric acid,  or  distillation  with  sulphuric  or  phosphoric 
acid  in  a  current  of  superheated  steam.  (Freund  :  Ann. 
Chem.  (Liebig),  120,  80;  Armstrong  and  Miller:  J. 
Chem.  Soc.,  45,  148;  Kelbe :  Ber.  d.  chem.  Ges.,  19, 
92). 

Hydrocarbons  are  universally  insoluble  in  water,  and 


CARBON    COMPOUNDS.  239 

dilute  acids.  The  hydrocarbons  of  the  marsh  gas  series 
are  nearly  or  quite  insoluble  in  concentrated  sulphuric 
acid  (see,  however,  Orndorff  and  Young  :  Am.  Chem. 
J.,  15,  261,  as  to  the  slow  absorption  of  propane  by 
fuming  sulphuric  acid).  Some  of  them  are  con- 
verted into  nitro  compounds  by  dilute  nitric  acid  (p. 
1 2 1 ) .  Unsaturated  hydrocarbons  decolorize  bromine  in- 
stantly, are  absorbed  by  concentrated  sulphuric  acid 
with  the  formation  of  acid  alkyl  esters  of  sulphuric  acid, 
and  reduce  cold,  neutral  solutions  of  potassium  perman- 
ganate instantly,  with  separation  of  manganese  dioxide. 
Aromatic  hydrocarbons  dissolve  in  concentrated  sul- 
phuric acid  with  the  formation  of  sulphonic  acids,  which 
remain  in  solution  on  dilution.  They  are  converted  into 
nitro  compounds,  which  remain  undissolved  on  dilution, 
by  concentrated  or  fuming  nitric  acid,  or  mixtures  of 
nitric  and  concentrated  sulphuric  acids.  Dinitro  and 
trinitro  compounds,  which  are  usually  solids,  are,  as  a 
rule,  most  suitable  for  purposes  of  identification. 

Alkaloids  give  precipitates  with  tannic  acid,  phospho- 
molybdicacid,  potassium  mercuric  iodide,  and  with  iodine 
in  an  aqueous  solution  of  potassium  iodide.  Like  amines 
they  usually  give  characteristic  crystalline  salts  with  chlo- 
roplatinic,  chlorauric  and  picric  acids.  Many  alkaloids 
may  be  extracted  from  alkaline  solutions  by  ether,  ben- 
zene, amyl  alcohol,  chloroform,  or  acetic  ester.  Most  of 
them  give  characteristic  color  reactions  of  various  kinds. 
For  details,  reference  must  be  had  to  some  work  on 
toxicology. 


240  ORGANIC   CHEMISTRY. 

Reagents* 

In  very  many  operations  in  organic  chemistry,  success 
depends  on  the  use  of  reagents  in  definite  quantities, 
and  in  almost  all  cases  it  is  an  advantage  to  know  quite 
accurately  how  much  of  each  substance  is  present. 
Students  should  acquire  the  habit,  therefore,  of  using 
solutions  of  known  strength,  and  of  weighing  or  meas- 
uring the  substances  and  solutions  used.  This  is 
greatly  facilitated  by  knowing  the  strength,  approxi- 
mately, of  the  common  laboratory  reagents,  and  by 
having  always  at  hand  certain  strong  solutions  of  sub- 
stances often  used.  Facility  in  making  quick,  approxi- 
mate calculations  of  quantities  reacting,  is  necessary, 
and  this  is  often  aided  by  using  the  number  of  grams, 
or  deci-,  or  centigrams  of  a  body  corresponding  to  its 
molecular  weight. 

Among  the  solutions  which  are  especially  useful  in 
organic  work,  and  which  are  of  strengths  different  from 
the  ordinary  laboratory  reagents,  may  be  mentioned  the 
following  : 

Hydrochloric  Acid, — Sp.  gr.  i.n.  One  cc.  contains 
0.25  gram  HC1,  or  4  cc.  =  i  gram  HC1.  One  gram 
contains  0.224  gram  HC1.  This  acid  is  approximated 
closely  by  diluting  concentrated  pure  hydrochloric  acid 
with  an  equal  volume  of  water. 

Sulphuric  Acid. — Sp.  gr.  1.55.  One  cc.  contains  i 
gram  H2SO4,  or  i  gram  contains  0.645  gram  H2SO4. 
This  acid  is  closely  approximated  by  diluting  pure  con- 
centrated sulphuric  acid  with  an  equal  volume  of  water 


REAGENTS.  241 

Sodium  Hydroxide. — Sp.  gr.'i.29.  Onecc.  contains 
0.335  gram  NaOH,  or  3  cc.  =  i  gram.  One  gram  con- 
tains 0,26  gram  NaOH.  The  solution  is  approximated 
closely  by  dissolving  335  grams  of  pure  sodium  hydrox- 
ide in  700  cc.  of  water,  and  diluting  the  solution  to  one 
liter,  when  cold.  The  solution  does  not  attack  glass  as 
readily  as  weaker  solutions. 

Sodium  Nitrite. — 5  cc.  =  i  gram.  Approximated  by  dis- 
solving 205  grams  of  crystallized  sodium  nitrite  in  800  cc. 
of  water,  and  making  the  volume  to  one  liter.  The  exact 
strength  can  be  determined  by  diluting  a  small  portion 
very  largely,  acidifying  with  dilute  sulphuric  acid,  and 
titrating  to  permanent  red  with  standard  potassium  per- 
manganate. The  end  reaction  is  slow. 

Many  other  solutions  will  suggest  themselves  to  any 
one  working  in  particular  lines,  but  further  details  are 
scarcely  necessary. 


INDEX. 


When  a  compound  is  mentioned  several  times,  the  page  on 
which  directions  for  its  preparation  are  given  is  placed  first,  in 
case  such  directions  are  given  in  the  book.  The  prefixes  para, 
ortho,  etc.,  are  not  regarded  in  the  arrangement;  thus ^-nitro- 
beuzoic  acid  is  given  under  the  letter  N. 

ACETACETIC  ESTER 44,  5>  7,  220,  222 

Acetaldehyde 181 

Acetamide 80 

Acetanilide 86,  136 

Acetic  anhydride 78,  58,     91 

Acetic  ester 87,     45 

Acetone,  chloroform  from 119 

Acetone,  semicarbazone  of 193 

Acetonitrile 86,     81 

Acetonyl  acetone 53 

Acetophenone,  preparation,  reduction 167 

phenyl  hydrazone  of 191 

Acetoxime 192,  141 

^>-Acettoluide 124 

Acetyl  chloride 76 

derivatives 91 ,     78 

group,  oxidation  with  a  hypochlorite 59,  1 19,  107 

tartaric  ethyl  ester 91 

"  Acid  "  decomposition 57,  9,  50,  55,  107 

Acid  sodium  sulphite,  compounds  with  ketones  and  alde- 
hydes    188,  181,     50 

Acid  sodium  sulphite,  preparation 188 

Acids,  derivatives  of 70 

amides 80,  82,  83,  227,     72 

amino 97,     99 

anhydrides 78,  79,     71 

chlorides 76,     70 

esters 87,  89,  92,     73 

halogen  derivatives • 93,     75 

inner  anhydrides  of  bibasic 71 

irnides 72 

nitro  derivatives 24,     95 

preparation  of I 


INDEX.  243 

Acids,  from  alcohols 12 

cyanides 32,34,     42 

by  condensation    44,  51,  53)  58,  59,  225 

decomposition  of  a  bibasic  acid 61,     1 1 

from  ketones 18,     20 

hydrocarbons 23,       2 

natural  products 63,  65,     67 

qualitative  characteristics  of 234 

separation  of  fatty 18,       2 

Acids,  uusaturated,  reduction  of 103,     76 

Acrolein 1 76 

Active  forms  of  mandelic  acid 42 

Alcohol,  use  as  a  solvent 29 

Alcohols,  preparation 164 

from  aldehyde    176 

halogen  derivatives 166 

ketones 167 

preparation  of  hydrocarbon  from 117,  206 

qualitative  characteristics  of 237 

Aldehyde  ammonia 183 

Aldehydes,  preparation 178 

from  alcohol , 181 

a  monochlor  derivative  of  a  hydrocarbon . .   187 

qualitative  characteristics 238 

Alicyclic  hydrocarbons 207 

Alizarin 172 

Alkaloids,  qualitative  characteristics 239 

Alkyl  sulphonamides 85 

Allocinnamic  acid 59 

Allyl  alcohol 175,     6r 

dibromide 176 

Allyl  aniine 131 

Aloxan 67 

Aluminium  chloride 211,184,205,206,  226 

Amalgam,  sodium 103 

Amides 80,  82,  83,  227,  100,  4,     72 

qualitative  characteristics  of 234 

Amiue  group,  replacement  by  bromine 114,   106 

cyanogen 42 

hydrogen 125,  208 

hydroxyl 168 

the  ethoxy  group 208 

Amines,  preparation 130 

from  amides 99,  132,   147 

cyanides 142,  132 


244  INDEX. 

Amines,  from  halogen  compounds 97,  144,  130 

liydrazoues 132 

paranitroso  compounds 138,  133 

oximes    140,  132 

urethanes    147 

separation  of  primary,  secondary  and  tertiary.  85,  235 

qualitative  characteristics 235 

Aminoacetic  acid 97 

Amiuoazo  compounds 155,  157,  149 

/-Aminoazo  benzene 155,  149 

0-Aminobenzoic  acid 99 

Aminoethanoic  acid 97 

i2-Aminoethylpheu 142 

i^Aminoethylphen 144 

Aminomethylphen 144 

Aminonitrotoluene  (4  :  2) 128,  135 

Aminonitrotoluene  (4  :  3) 125 

2-Aminopropaue 140 

/>-Aminosulphobenzene 200 

Ammonium  acetate 80 

Amyl  alcohol,  oxidation 12 

Anaesthetic,  ethyl  bromide  for  an no 

Angelica  lactone 69 

Anhydrides  of  acids 78,  70,  71 

Anilides 86,  73 

Aniline 133 

Aniline  chloride 156 

hydroquinone  from    170 

sulphonic  acid  of 200 

' '  Aniline  yellow  " 157 

Anthracene 215,  190,  174 

Anthranilic  acid 99 

Anthraquinone 190,  172,  227 

Anthraquinonediol    172 

Anthraquinone  monosulphonic  acid 173 

Antifebrin 87 

Antipyrine    222 

Aromatic  series,  nitro  derivatives  of 

• •  •  •  • 25,  123,  124,  127,  128,  135,  136,  121 

Arsenic,  detection  in  ethyl  bromide in 

tests  for 231 

acid  in  Skraup's  synthesis 218 

Autoclave,  use  for  alkali  fusions 174 

Auxochrome  groups 150 

Azobenzene 154 


INDEX.  245 

Azo  compounds  and  dyes 154,  155,  157,  148,  150,  201 

Azoxy  compounds 148 

OARIUM  salts  of  nitrobenzoic  acids 30,  97 

Beckmauu's  mixture  for  oxidizing  alcohols 178 

rearrangement 186 

Benzal  acetone 60 

chloride 114 

Benzaldehyde 187,188,176,58,  60 

Benzamide 227 

Beuzene-azo-malonic  ester 152 

Benzene-azo-fl-naphthylamine  sulphonic  acid 157 

Benzene,  bromiuation  of m 

condensation  with  benzoyl  chloride 184 

dipheayl  from 213 

nitration   123 

preparation  from  benzoic  acid 209 

sulphonic  acid  of - 83 

Benzidine    154 

Benzil 189 

Benzoic  acid 23,  92,  209 

ethyl  ester 92 

sulphinide 203 

Benzoin 188 

stereoisomerism  of  oximes  of 189 

Benzonitrile 227 

Beuzophenone  184 

boiling-point  with  varying  pressures 185 

reduction  by  hydriodic  acid 215 

stereoisomerism  of  oximes 186 

Benzoquinone 170 

o-Benzoy Ibenzoic  acid 225 

Beuzoyl  chloride 92,  86,  184 

derivative  of  a  phenol 85 

Benzyl  acetacetic  ester 55 

acetone 58 

alcohol 176 

amine 144,  131 

chloride 112,  142 

oxidation  of 23 

cyanide 142 

Bibasic  acids,  decomposition  of 61,  n 

' '  Bleaching  powder, ' '  preparation  of  chloroform  with 119 

Boiling-points,  correction  for 16,  17 

Bromination 111,105,93,  75 


246  INDEX. 

/>-Brombenzoic  acid 117 

Brom-2-butanoic  acid ' 93 

<z-Brombutyric  acid 93 

Bromine  derivatives  of  acids 93,  75 

through  diazo  compounds 114 

measurement  of 94 

tests  for 231,  232,  233 

/>-Bromtoluene 1 14,  210 

Bunseu  pump 48 

Butane,  chloriuation  of 105 

Butanoic  acid 18,  93 

3-Butanonic  ethyl  ester 44 

i3-Butylouphen 58 

Butyric  acid 18,  93 

CAD  AVERIN 344 

Calcium  chloride,  drying  with 15,25,51,109,  119 

combination  of  benzyl  alcohol  with 177 

hypochlorite,  preparation  of  chloroform  by 119 

salts 19,  37 

Camphor 20,  212 

Camphoraminic  acids 21,  22 

Camphoric  acid 20 

anhydride  and  imide 22 

Camphoronic  acid 22 

Cane  sugar,  levulinic  acid  from 67 

Carbamide > 82 

Carbides,  hydrocarbons  from 208 

Carbohydrate,  levulinic  acid  from    67 

furfural  from 196 

Carbon  compounds,  qualitative  examination 23 1 

Carbonyl  chloride,  urea  from 82 

Chapman  filter  pump 48 

Chlorides  of  acids 76,82,83,201,227,70,  73 

Chloride  of  sulphuric  acid 201 

Chlorination,  direct 112,  105 

of  butane 105 

Chlorine,  preparation 112 

substitution  in  side  chain 112 

tests  for 231,  232,  233 

Chloroform 119,107,  60 

Chromic  acid,  oxidation  with 12,  170,  182,  190,  18,  178 

"  Chromophor  "  groups 150 

Cinnamic  acid 58,  59,  103,  9 

Ciscrotonic  acid 95 


INDEX. 


247 


Claisen  distilling  bulb 47 

Collidine 222 

Collidiuedicarboxyllic  ester 220 

Condensation 4 

of  acetic  to  acetacetic  ester 44 

acetacetic  ester  with  a  halogen  compound  55,  7 

acetacetic  ester  with  itself 51 

acetone  with  benzaldehyde 60 

an  aldehyde  with  the  sodium  salt  of  an  acid 

58,  9 

aldehyde  with  itself 188 

a  diazo  compound  with  amines  and  phenols 

•••;••':':••••••-••-•''  155,157,  149 

by  means  of  aluminium  chloride  184,  210,  225,  205 

of  ketones  to  hydrocarbons 212,  207 

Condenser,  upright  or  reversed 13 

Copper  zinc  couple 228,  206' 

Corncobs,  furfural  from 196 

Corrections  for  boiling-points  and  melting-points 16,  17 

/>-Cresol 168 

Crystallization 27,  54 

Cuprous  bromide  for  Sandmeyer's  reaction 1 14 

Cyanhydrines 37,  3 

Cyanides  or  nitriles 32,  35,  38,  142,  227;  2,  4,  81 

amines  from 142,  132 

Cyclic  acids 76 

ketones 178 

i  ,4-Cyclohexanedion 55 

Cymene 212 

DECOMPOSITION,  "acid"  and  "  ketonic  ". ..  50,  55,  57,  8 

of  bibasic  acids 61,  n 

Dehydracetic  acid 50 

Derivatives  of  acids 70 

aldehydes  and  ketones....   191,  192,  193,  178,  180 

Dextrosazone 162 

Diacetyl  succinic  ester 51 

tartaric  ethyl  ester 89 

Dialkyl  sulphonamid.es 85 

/>-Diaminobenzene '• 136 

Diazoaminobenzene 155,  149 

Diazobenzene  chloride 159 

Diazo  compounds 150 

azo  compounds  from 155,  157,  149 

cyanid es  from 42,  3 


248  INDEX. 

Diazo  compounds,    discussion    of    decomposition  in  Saiid- 

meyer's  reactions 115 

halogen  compounds  from 115,  106 

hydrazine  from 160 

hydrocarbons  from 125,  208 

phenol  from 168 

Dibenzal  acetone 60 

Dibenzyl 190,  148 

acetacetic  ester 57 

Dibromallyl  alcohol 176 

/>-Dibrombenzene m 

Dibromcinnamic  acid 59 

Dibromethane 117 

Diethyl  amine • 138,  133 

Dihydrocollidinedicarboxyllic  ester 221 

Dihydroxy  acids V  '  * '  : l65 

Dihydroxyquinone  from  a  sulphonic  acid 172 

Diketohexamethylene  55 

i,  4-Dimethylphen 209 

ra-Dinitrobenzene • • 123 

Dinitrotoluene  (2:4) 135 

Dioxyterephthalic  acid 55 

Diphenyl 213 

Diphenyluiethane 214,  212 

Diphenylmethanone 184 

Diphenylmethanonmethyllic  acid 225 

Diphenylsulphone 84 

Dipropylketone    18 

Distillation,  fractional 15 

under  diminished  pressure 46,     48 

with  air  condensing  tube 15 

steam 13,14,     *9 

Distilling  bulb,  Claisen 47 

Ladenburg 47 

"  Division  coefficient  " 39 

Dry  ether ." : '  : 5*,     52 

Drying  under  diminished  pressure  in  distilling  bulb 36 

with  calcium  chloride 15,  25,  51,  109,   119 

Dye  stuffs,  characteristics  of 15° 

Dyes,  azo 15°.  *55.  157.  2O1 

*  *  ENOI/'  form  of  acetacetic  ester 5 

Bsterification,  theory  of 74 

Esters,  amides  from 72 

preparation 87,  89,  92,  73,  80,  34 

saponifi  cation II 


INDEX.  249 

Ethanol 181 

Ethanediol 166 

Ethanoic  acid,  ethyl  ester  of 87 

anhydride 78 

Ethanoyl  chloride  76 

Ether,  purification,  drying,  preservation 51,  52 

use  in  extraction 38 

Ethyl  aniline 138 

bromide 109,  138 

Ethylene 117 

bromide 117,32,33,  166 

cyanide 33,  144 

glycol : 166 

Ethyl  nitrite  •    159,  125 

zinc  iodide 229 

sulphuric  acid,  ethyl  bromide  from no 

Extraction  with  ether 38 

F*AT,  saponification  of 63 

Fatty  acids,  separation  of 18,  2 

sulphonic  acids  of 198 

Ferric  bromide,  used  in  bromination in 

chloride,  color  reactions 50,  99,  103 

Filtration  of  a  hot  solution  for  crystallization 29,  54 

^with  Witt  plate  or  Hirsch  funnel 21 

Fluoresce'in 220 

Formaldehyde,  hexamethylene  amine  from 145 

Formic  acid 61,  68,  175,  n 

Fractional  distillation 15,  ,210 

Friedel  and  Craft's  reaction 184,  210,  226,  205 

Furfural 196 

Furfuramide 197 

Furoin 197 

Fusel  oil,  oxidation 12 

Fusion  of  a  sulphonic  acid  with  potassium  hydroxide 172 

GLUCOSIDES ii 

Glucose   68,  162 

Glucosazone 162 

Glutaric  acid  and  derivatives,  anhydrides  of 71 

Glycerol 61,  175 

Glycocoll 97 

Glycollic  acid 99,  167 

Glycols 166,  165 


250  INDEX. 

H AIvOGEN  compounds 105 

from  alcohols •  ••  108,  109,  106 

amines 114,  106 

hydrocarbons  •   in,  112,  117,  106 

qualitative  characteristics  of 235 

derivatives  of  acids 75 

Halogens,  tests  for 231,  232,  233 

Hell-Volhard-Zelinsky     method    for    the   brotnination    of 

acids 93>  75 

4-Heptanone I° 

Hexamethylene  amine 144.  I31 

compounds  transformed  to  pentamethylene 

by  hydriodic  acid 208 

Hirsch  funnel 2I 

Hoffmann's  reaction 100,  147,  99 

Hydrazides T52>  223 

Hydrazines.... l6o>  *5i 

Hy drazo  compounds 153>  I4o>  I5° 

Hydrazobenzene J53 

Hydrazones I9I>  ^  l8° 

amines  from *32 

Hydriodic  acid,  reduction  of  ketones  by 214,  208 

Hydrocarbons 2°5 

qualitative  characteristics  of 238 

Hydrocinnamic  acid 55>  IO3 

Hydrocyanic  acid,  use  in  benzaldehyde 188 

Hydrogen  sulphide T37 

Hydrolysis  of  a  pentosan 197 

Hydroquinone I7° 

Hydroxy  acids 101,37,  76 

acid,  ester  and  acetyl  derivative  of 89 

Hydroxyanthraquinone J73 

Hydroxyazo  compounds 149 

Hydroxybutyric  acid 95 

Hydroxyvaleric  acid  • • 69 

Hydroxypropylbenzoic  acid 213 

Hypochlorites,  use  to  oxidize  the  acetyl  group 60,  119,  107 

Hypobromite,  use  in  Hoffmann's  reaction 100,  147 

I  HIDES,  qualitative  characteristics  of 234 

Immiscible  solvents 39 

Indigo,  anthranilic  acid  from IO1 

Iodine,  tests  for 231,  232,  233 

lodoso  compounds    2O° 

Isocinnamic  acid 59 


INDEX.  251 

Isonitrosoacetone 192 

Isopropyl  amine 140 

Isosulphocyanides 236 

Isovaleric  acid 12,  i 

ICETONES 178 

from  chlorides  of  acids 184,  167  179 

salts  of  acids 18,  178,  168 

reduction  of 167 

"  Ketonic  "  decomposition 50,  55,  57,  8 

Knoevenagel's  synthesis 10 

Kohnlein's  method  for  preparing  hydrocarbons 206 

Kolbe's  synthesis  of  hydroxy  acids 101,  76 

"  Kuppelung" 150 

L  ACTONE,  angelica 69 

valero 69 

Law  of  division  for  immiscible  solvents 39 

4 '  I/euco  ' '  compounds 150 

Levulinic  acid  from  a  carbohydrate 67 

Levulosazone 162 

Liebermann's  reaction  for  secondary  amines 236 

7VYAGNESIUM  acetate,  solution  of 63 

Malonic  diethyl  ester 34,       9 

Mandelic  acid*. 37 

Manuesmann  tube 174 

Manometer 49 

Marsh  gas  series,  nitro  derivatives  of 121 

Melting-points    30 

correction  for 16 

Mesoxalic  acid  from  aloxan 67 

hydrazone  of 152 

Metaldehyde 184 

Metanilic  acid 201 

Methanoic  acid 61 

3-Methylbutanoic  acid 12 

3-Methylbutanol,  oxidation 17 

Methyl  cyanide 81 

Methylene  diethyl  ether 146 

Methyl  iodide 108 

/-Methylisopropylphen 212 

^-Methylphenol 168 

Monochloracetic  acid 34,  97 

Monohalogen  derivatives  of  the  ethylene  series 106,  166 

"  Monohydrate,"  sulphuric  acid 96 


252  INDEX. 

Mordants,  effect  on  alizarin  ................................  174 

"  Murexid  "  reaction  for  uric  acid  .........................  66 

Mustard  oils  ..............................................  236 


amine,  azo  compound  from  ..................    158 

Naphthalene,  nitration  of  .................................    127 

tetrahydride  ................................   208 

Nitrate  of  urea  .......................................    194,     83 

Nitration  of  acetanilide  ....................................   136 

acettoluide  ...................................    124 

benzene  .......................................    123 

naphthalene  ..................................    127 

toluene  ...................................  25,  135 

toluidine  .....................................  128 

urea  ..........................................    194 

laws  of  position  of  groups  in  .....................   122 

Nitric  acid,  oxidation  with  .............................   20,     23 

in  tests  .........................  231 

Nitriles  ............................  33,  35,  38,  43,  227,  2,  3,     81 

amines  from  ............  .  .....................   142,  132 

qualitative  characteristics  of  .......................   234 

Nitroacetanilide,  reduction  ................................    136 

Nitroacettoluide  (3:4)  .....................................    125 

Nitrobenzene,  reduction  ...................................    136 

o-  and  ^-Nitrobenzoic  acid  .............................   24,  100 

w-Nitrobenzoic  acid  .......................................     95 

Nitro  compounds  ..........................................   121 

qualitative  characteristics  ................   235 

reduction  .......................    133,  135,  136 

Nitrogen,  tests  for  ............................    .......   232,  233 

#-Nitronaphthalene  .......................................   127 

Nitrophthalic  acid  .....    ..................................    127 

o-  and  /-Nitrotoluene  ......................................     25 

ra-Nitrotoluene  ...........................................   124 

Nitroso  compounds  ...................................   139,  148 

/-Nitrosodiethyl  aniline  ..............................   138,  133 

^-Nitrosophenol  ...........................................    139 

Nitrotoluidine  (3:4)  ........................  ..............    125 

(2:4)  .................................   128,  135 

Nitrourea  ............................................    194,     83 

Nitrous  anhydride  (so-called)  preparation  .................   222 

OIL  of  bitter  almonds  ...................................  187 

Oleic  acid  .................................................  64 

Osazones  .........................  ...................   162,  152 

Oxalic  acid,  decomposition  of  .............................  61 


INDEX.  253 

Oxidation  with  a  nitrate 187 

chromic  acid 12,  18,  170,  178,  181,  190 

nitric  acid 20,     23 

potassium  permanganate 24,  165 

sodium  hypochlorite 59 

Oximes 192,  180 

amines  from 140,  132 

0-Oxybenzoic  acid 101 

/•-Oxybenzoic  acid 103 

Oxyazo  compounds 149 

F>ALMITIC  acid 64 

Paraldehyde 184 

Pentamethy lene  compounds  from  hexamethylene 208 

Perkin's  synthesis 58,       9 

Phen 209 

"  Phenathylsaure  " 55 

i,  4-Phendiol 170 

Phenethylol  (i) 167 

Phenethylolic  acid 37 

Phenmethylol 176 

Phenol,  benzoy  1  derivative  of 86 

phthalein 218 

Phenols,  amines  from 133 

from  amines 168,  170,  164 

sulphonic  acids 172,  165 

hydroxy  acids  from 101 

qualitative  characteristics  of 237 

Phen-3-propanoic  acid 55,  103 

Phenyl  benzoate 86 

cyanide 227 

reduction 144 

i-Phenyl-2,  3-dimethylpyrazolone 222 

/-Phenylenediamine 136 

#/-Phenylethylamine 142 

Phenyl  hydrazine 160,  191 

hydrazone  of  acetophenone 191 

methyl  carbinamine 191 

carbinol ••••..   167 

i-Phenyl-3-methylpyrazolone 223 

Phenyl  propiolic  acid 59 

sodium  carbonate 101 

sulphonchloride 85 

use  in  separating  amines 85 

sulphonamide 83 


254  INDEX. 

Phosgene,  urea  from 82 

Phosphorus  oxychloride,  action  on  acids  and  salts 79,     70 

pentachloride      "       "       "         "     "     80,  92,  70,  106 

pentoxide,  hydrocarbon  from  a  ketone  by 212 

nitrile  from  amide  by 227 

to  dry  ether 52 

tests  for 232 

trichloride,  action  on  acids 76,     70 

trisulphide,  thiophen  by 225 

Phthalamidic  acid 100 

Phthalicacid 127 

anhydride,  anthranilic  acid  from 99 

condensation  with  benzene 226 

phenols 218 

Pinacone  from  acetophenone 168 

Potassium  bromide 109,  114 

cyanide  as  a  condensing  agent 188 

permanganate,  oxidation  with •• 26,  165 

test  for  unsaturated  compounds-    104 

phenolate  103 

phthaliuiide,  use  in  preparing  amines 130 

Primary,  secondary  and  tertiary  carboxyl,  esterification  of  • .     74 

amines,  separation  of 85 

nitro  compounds,  chemical 

character  of 85 

Propanoic  acid 18 

Propanone  oxime 192 

Propionic  acid  18 

Pyrazolone  derivative 222 

Pyridine  derivative  by  condensation 220 

Pyrogenic  reaction,  hydrocarbon  by 213 

QUALITATIVE  examination  of  carbon  compounds 23 1 

Quinoline,  Skraup's  synthesis  of 217 

use   in   preparing    hydrocarbons   from    halogen 

compounds 206 

Quinones 171,  190,  180 

REAGENTS 240 

Reduction  of  a  cyanide  or  nitrile 142 

diazo  compound 160,  151 

hydrazone 132 

ketone  by  sodium 167 

hydriodic  acid 214 

an  oxime 141 


INDEX.  255 

Reimer-Tiemann's  reaction 76 

Replacement  of  an  amine  group  by  bromine 114 

cyanogen 42 

hydrogen 125,208 

hydroxyl 168 

Reversed  condenser 13 

' '  SACCHARINE  " 203 

Salicylic  acid 101 

Sandnieyer's  reaction,  discussion 115 

for  the  preparation  of  a  cyanide.  42,       3 
bromine 

compound 114,  106 

Sealing  tubes 81 

Semicarbazide 195 

Semicarbazones 193,  196  181 

Saponificatiou  of  a  cyanide 32,  35,  38,       2 

fat 63 

Separation  of  the  active  forms  of  mandelic  acid 42 

fatty  acids 18,       2 

Separatory  funnel 25 

use  in  ether  extractions 40 

Skraup's  synthesis  of  quinoline 217 

Silver  butyrate  and  proprionate 20 

nitrate  as  a  test  for  aldehydes 184,  191 

Soda-lime,  use  to  prepare  a  hydrocarbon 209 

Sodium  amalgam 76 

ethy late,  condensation  by 44,  53,       5 

hydroxide,  reagent 241 

hypobrotnite,  use  in  Hofmann's  reaction 100 

hypochlorite,  oxidation  of  acetyl  group  with 60 

nitrite,  reagent 241 

phenolate 101 

P^ss 45 

pyrochroniate 12,  102 

sulphite,  preparation  of  acid 188 

wire 45 

Solidification  of  ^-cresol 170 

Solvents,  immiscible 39 

use  of 28,     29 

Stannous  chloride 160 

Steam  distillation 13 

with  reversed  condenser 14 

Stearic  acid 63 

Stearin 12 


256  INDEX. 

Stilbene,  formation  by  reduction  of  a  nitro  compound 148 

Sublimation 1 74 

Succinate  of  sodium,  thiophen  from 225 

Succinic  acid 32 

and  derivatives,  anhydrides  of 71 

diethyl  ester 89,  53 

monoethyl  ester 80 

anhydride 79 

ester 89,  53 

Succinylosuccinic  ester 53>  6 

Sugar,  leyulinic  acid  from 67 

Sulphaminebenzoic  acids 202 

Sulphanilic  acid 200 

azo  compound  from 158 

Sulphine  compounds 203,  199 

/-Sulphobenzen-azo-0-naphtylamine 1 57 

Sulphonamide,  phenyl 83 

toluene 201 

Sulphonate,  sodium  benzene  . 83 

anthroquinoiie 1 73 

Sulphonchloride,  phenyl • • 85 

use  of  in  separating  amines 85 

Sulphonchlorides  of  toluene,   from  chloride   of  sulphuric 

acid 201 

Sulphone,  diphenyl 84 

Sulphonic  acids I98>  200,  173,  84,  172 

phenols  from 1 72>  ^5 

qualitative  characteristics  of 238 

Sulphur  dioxide *72 

Sulphuric  acid,  chloride  of 201 

"  monohydrate  " 96 

Sulphur,  tests  for 231,  232,  233 

TALLOW 63 

Tartaric  acid,  diacetyl  diethyl  ester  of 89 

diethyl  ester  of 89 

Terephthalic  acid  from  cymene 213 

toluic  acid 44 

/>-xylene • 210 

Tetrabromfluorescein 220 

Tetraldehyde l84 

Thermometers,  testing  and  correction  of io 

Thiocarbamic  acids,  derivatives  of 236 

Thiophen  from  sodium  succinate 224 

Toluene,  ^-brom •••  IJ4 


INDEX.  257 

chlorination  in  side  chain 112 

nitration  of 25,  135 

m-nitro   124 

sulphonamides  and  sulphonchlorides  of 201 

/-Toluic  acid  from  cytnene 213 

toltiidine 42 

/•-xylene 210 

/-Toluidine,  ^-acettoluide  from 1 24 

/>-cresol  from  168 

nitration  of 128 

/>-toluic  acid  from 42 

^-tolunitrile  from 42 

Trichlormethane 119 

Trimethylene  cyanide,  reduction  of 144 

Trimethyl  sulphine  iodide. 203 

Trinitrotriphenylmethane 212 

Triphenylmethane 210 

Tubes,  sealing  of 8r 

UNSATURATED  acids,  reduction  of 103,     76 

alcohol 1 75 

Upright  condenser 23 

Urea 82 

formation  from  aloxan 67 

nitrate 194,     83 

nitro 194 

use  in  preparing  a  phenol 169 

Urethanes,  use  in  preparing  amines 147 

Uric  acid 65 

VALERIC  acid,  iso 12 

hydroxy 69 

Valerolactone 69 

Volatile  liquids,  preservation  of 52,  109 

Vinyl  bromide 119,  166 

1A7 ASHING  soluble  substances 21 

Witt  plate 21 

/>-J?Cylene,  preparation 209 

ZINC  alkyl  compounds,  hydrocarbons  from 205 

chloride  as  a  condensing  agent 133,  220 

copper  couple 206,  228 

dust,  reduction  by  distillation  with 215 

ethyl '^^^^!^^L 228 


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